I think the book can be of great value to --- wants to go to

whoever=him (her,them)+he (she,they)
whomever= him(her,them)+ him (her,them)
验证一下：
1.Give it to _____ asks for it first.
Give it to him.He asks for it first.
Therefore,Give it to whoever asks for it first.(whoever= him+ he)
2.We will hire_______ is most qualified.
We will hire her.She is most qualified.
Therefore,We will hire whoever is most qualified.(whoever= her+ she)
3.We will hire_____ you recommend.
We will hire them.You recommend them.
Therefore,We will hire whomever you recommend.( whomever= them + them)
所以很显然 选择 B