请阅读下面短文，根据短文内容，从方框内所给的选项中选出能填入空白处的最佳选项，使短文意思通顺。

    David likes doing sports, but he doesn't have any things for sports. He wants to buy a volleyball and two pairs of ping-pong bats, too. He goes to the sports store. He thinks their prices are good, so he takes a basketball, a volleyball and two pairs of ping pong bats. And then he wants to buy a soccer ball. He thinks it's a little expensive.

    “I want it for $12. Is that OK?" says David to the salesman (售货员).

    So he buys a soccer ball, too. He is really happy.

A. They are $29 in all. B. So he wants to buy a basketball. C. The basketballs are $ 10, volleyballs are $9 and ping pong bats are $5 a pair. D. The salesman says yes to David. E. But soccer balls are $15.