Need jquery code to disable radio buttons when a option in dropdown is selected in sharepoint

I am working with moss 2007. I created a drop down column in which has 3 options. If option1 and option 2 are selected the radio button columns should be disabled and if option 3 selected the Radio button columns should be enabled. I provided the page source code, could someone help me out with this with some coding since i am newbie to jquery.

<TR>
            <TD nowrap="true" valign="top" width="190px" class="ms-formlabel"><H3 class="ms-standardheader">
            <nobr>Type of Notification</nobr>
        </H3></TD>
            <TD valign="top" class="ms-formbody" width="400px">
            <!-- FieldName="Type of Notification"
                 FieldInternalName="Type_x0020_of_x0020_Notification"
                 FieldType="SPFieldChoice"
              -->
                <span dir="none"><select name="ctl00$m$g_785c653c_cfa1_4aa5_8060_a84901274cc3$ctl00$ctl04$ctl07$ctl00$ctl00$ctl04$ctl00$DropDownChoice" id="ctl00_m_g_785c653c_cfa1_4aa5_8060_a84901274cc3_ctl00_ctl04_ctl07_ctl00_ctl00_ctl04_ctl00_DropDownChoice" title="Type of Notification" class="ms-RadioText">
        <option selected="selected" value="Select One">Select One</开发者_开发百科option>

        <option value="Option1">Option1</option>
        <option value="Option2">Option2</option>
                  <option value="Option3">Option3</option>

    </select><br></span></TD></TR>

    <TR>
            <TD nowrap="true" valign="top" width="190px" class="ms-formlabel"><H3 class="ms-standardheader">
            <nobr>Does this position have direct reports</nobr>
        </H3></TD>
            <TD valign="top" class="ms-formbody" width="400px">
            <!-- FieldName="Does this position have direct reports"
                 FieldInternalName="Does_x0020_this_x0020_position_x0"
                 FieldType="SPFieldChoice"
              -->
                <span dir="none"><table cellpadding="0" cellspacing="1">
        <tr>
            <td><span class="ms-RadioText" title="Yes"><input id="ctl00_m_g_785c653c_cfa1_4aa5_8060_a84901274cc3_ctl00_ctl04_ctl09_ctl00_ctl00_ctl04_ctl00_ctl00" type="radio" name="ctl00$m$g_785c653c_cfa1_4aa5_8060_a84901274cc3$ctl00$ctl04$ctl09$ctl00$ctl00$ctl04$ctl00$RadioButtons" value="ctl00" /><label for="ctl00_m_g_785c653c_cfa1_4aa5_8060_a84901274cc3_ctl00_ctl04_ctl09_ctl00_ctl00_ctl04_ctl00_ctl00">Yes</label></span></td>
        </tr><tr>
            <td><span class="ms-RadioText" title="No"><input id="ctl00_m_g_785c653c_cfa1_4aa5_8060_a84901274cc3_ctl00_ctl04_ctl09_ctl00_ctl00_ctl04_ctl00_ctl01" type="radio" name="ctl00$m$g_785c653c_cfa1_4aa5_8060_a84901274cc3$ctl00$ctl04$ctl09$ctl00$ctl00$ctl04$ctl00$RadioButtons" value="ctl01" checked="checked" /><label for="ctl00_m_g_785c653c_cfa1_4aa5_8060_a84901274cc3_ctl00_ctl04_ctl09_ctl00_ctl00_ctl04_ctl00_ctl01">No</label></span></td>
        </tr>
    </table></span></TD></TR>

    <TR>
            <TD nowrap="true" valign="top" width="190px" class="ms-formlabel"><H3 class="ms-standardheader">
            <nobr>Spectris Approver</nobr>
        </H3></TD>
            <TD valign="top" class="ms-formbody" width="400px">
            <!-- FieldName="Spectris Approver"
                 FieldInternalName="Spectris_x0020_Approver"
                 FieldType="SPFieldChoice"
              -->
                <span dir="none"><table cellpadding="0" cellspacing="1">
        <tr>
            <td><span class="ms-RadioText" title="Yes"><input id="ctl00_m_g_785c653c_cfa1_4aa5_8060_a84901274cc3_ctl00_ctl04_ctl19_ctl00_ctl00_ctl04_ctl00_ctl00" type="radio" name="ctl00$m$g_785c653c_cfa1_4aa5_8060_a84901274cc3$ctl00$ctl04$ctl19$ctl00$ctl00$ctl04$ctl00$RadioButtons" value="ctl00" /><label for="ctl00_m_g_785c653c_cfa1_4aa5_8060_a84901274cc3_ctl00_ctl04_ctl19_ctl00_ctl00_ctl04_ctl00_ctl00">Yes</label></span></td>
        </tr><tr>
            <td><span class="ms-RadioText" title="No"><input id="ctl00_m_g_785c653c_cfa1_4aa5_8060_a84901274cc3_ctl00_ctl04_ctl19_ctl00_ctl00_ctl04_ctl00_ctl01" type="radio" name="ctl00$m$g_785c653c_cfa1_4aa5_8060_a84901274cc3$ctl00$ctl04$ctl19$ctl00$ctl00$ctl04$ctl00$RadioButtons" value="ctl01" checked="checked" /><label for="ctl00_m_g_785c653c_cfa1_4aa5_8060_a84901274cc3_ctl00_ctl04_ctl19_ctl00_ctl00_ctl04_ctl00_ctl01">No</label></span></td>
        </tr>
    </table></span></TD>
        </TR>

Regards SP.D

$(document).ready(function(){
    $('.ms-RadioText').change(function(){
        var opt = $(this).val();
        if(opt == 'Option1' || opt == 'Option2'){
            $('input:radio').attr('disabled', 'disabled');
        } else{
            $('input:radio').removeAttr('disabled');
        }
    });
});

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