Checkboxes for discrete option in the inspector

Is there some annotation so that I can make the user(developer) select one of several discrete options for a unity script?

It would look similar to a public bool. So in the Inspector in unity when you expand the script component you would get something like:

Option_foo a b c

But a user can only have one of the options selected at one time.

And I hope that in the scipt “MyScript.cs” this would look something like:

[DiscreteOption(options="[a,b,c]")]
public string Option_foo;

How about enumeration?

public enum DiscreteOption{a,b,c}

public class MyClass:MonoBehaviour{
   public DiscreteOption option;
}

else you need to tell more.