If the price of potatoes is $0.20 per poun

问题：

If the price of potatoes is $0.20 per pound, what is the maximum number of potatoes that can be bought for $1.00 ？（）
(1)The price of a bag of potatoes is $2.80.
(2)There are 15 to 18 potatoes in every 5 pounds.

A．条件(1)充分，但条件(2)不充分．

B．条件(2)充分，但条件(1)不充分．

C．条件(1)和(2)单独都不充分，但条件(1)和条件(2)联合起来充分．

D．条件(1)充分，条件(2)也充分．

E．条件(1)和条件(2)单独都不充分，条件(1)和条件(2)联合起来也不充分．