Make attributes for:
Option Manager ...
Option Name: Shipped (or whatever)
Option Type: Radio
Option Value Manager ...
Option Name: Shipped
Option Value Name: Fresh
Option Default Sort Order: 10
Option Name: Shipped
Option Value Name: Frozen
Option Default Sort Order: 20
Option Name: Shipped
Option Value Name: Select a method
Option Default Sort Order: 0
Attributes Controller:
Option Name: Shipped
Option Value: Fresh
Option Name: Shipped
Option Value: Frozen
Option Name: Shipped
Option Value: Select a method
Default: YES
Display Only: YES
Once the 3 are made, hit the Update Sort Order and they will display in order the way you set them on defaults ...
Now the customer has to make a proper choice of one or the other as they cannot add Select a method to the cart as it is marked Display Only ...
To remove those, there is not a switch ...
You could however do a global update to physically remove all attributes with the options_id and options_values_id that match if needed ...