How to word question to indicate default answer in console application?

How to word question 开发者_JAVA技巧to indicate default answer in console application?

• Coca-Cola size [] Medium [S] Small [L] Large
• Coca-Cola size [Enter] Medium [S] Small [L] Large
• Coca-Cola size [Medium] [S] Small [L] Large

Other suggestions?

I like the way certain Linux stuff does it:

Allow non-root access (Y/N) [default=N]: _

For your specific use case, you could do:

Coca-Cola size (M)edium, (S)mall or (L)arge [default=M]: _