求助一道GWD

请大牛解释一下，谢谢

Q30:

Joanna bought only $0.15 stamps and $0.29 stamps.  How many $0.15 stamps did she buy?

(1)
              She bought $4.40 worth of stamps.

(2)
              She bought an equal number of $0.15 stamps and $0.29 stamps.

答案是 D

我怎么觉得答案是A啊。。。