A、  B、  C、  B本句是询问点完餐过了多久的How疑问句。应该理解How long…是询问时长的表达。

Shouldn’t we inform Mr. Simmons of the change in schedule?
(A)No, the fifth of July.
(B)The end of the year.
(C)I told him an hour ago.

How long has it been since you ordered the food?
(A)I’d like the pizza, please.
(B)I can’t remember.
(C)21 cents.