单选题 What does "them" refer to in the sentence "It sent them streaming westward into the wilderness after their predecessors to raise still more children who wanted still more land" ?

A、 Urban dwellers.
B、 Dollars and cents.
C、 Yearners.
D、 Predecessors.

【正确答案】 C

【答案解析】[解析] 见最后一段The obsession brought shiploads of yearners every week to Boston… and Savannah。从这句话可以看出them指的是C项的yearners。