Question

How many ____ do you want?

1. A.
   rice
2. B.
   tomatos
3. C.
   pieces of bread
4. D.
   potato

Answer 1

C
how many 对可数名词提问后跟可数名词复数形式，所以A和D不对，B答案的
复数应该是加es，所以也不正确，故选C。