求PREP-PS-1-193 思路

193.
                20944-!-item-!-187;#058&013354

A basket contains 5 apples, of which 1 is spoiled and the rest are good.  If Henry is to select 2 apples from the basket simultaneously and at random, what is the probability that the 2 apples selected will include the spoiled apple?

(A)  1/5

(B)  3/10

(C)  2/5

(D)  1/2

(E)  3/5

答案是C.

怎么解不出来是2/5？ 请高手帮忙！多谢