Tom is the boy _________ , everyone thinks, will win the first p

Tom is the boy _________ , everyone thinks, will win the first prize.
A、who
B、whom
C、whoever
D、he
【正确答案】：A
【题目解析】：考察定语从句，先行词为boy ，因此此处要用关系代词who 来引导从句，在从句做主语。