Task: Question Answering
Input (English): Problem: a university cafeteria offers 4 flavors of pizza - pepperoni , chicken , hawaiian and vegetarian . if a customer has an option ( but not the obligation ) to add extra cheese , mushrooms or both to any kind of pizza , how many different pizza varieties are available ? 
Options: a ) 4 , b ) 8 , c ) 12 , d ) 16 , e ) 32
Output (English): d