PREP SC 一道题不会做，求助！

azhongzhong

Both the caribou and the reindeer (belong to the species Rangifer tarandus, but after 7,000 years of domestication in Eurasia, reindeer have developed a tendency to circle in tight groups, while caribou tend) to spread far and wide.
 
A. belong to the species Rangifer tarandus, but after 7,000 years of domestication in Eurasia, reindeer have developed a tendency to circle in tight groups, while caribou tend  
 
 B。belong to the same species, Rangifer tarandus, but about 7,000 years of domestication in Eurasia have developed reindeer's tendency to circle in tight groups, which is different from caribou that tend  
 
C belong to the species Rangifer tarandus, but being domesticated in Eurasia for about 7,000 years has developed reindeer's tendency to circle in tight groups, and that is different from caribou tending  
 
D are the same species, Rangifer tarandus, but about 7,000 years of domestication in Eurasia have developed reindeer's tendency to circle in tight groups, while the tendency is for caribou  
 
 Eare the same species, Rangifer tarandus, but being domesticated in Eurasia for about 7,000 years has developed the reindeer's tendency to circle in tight groups, which differs from caribou tending  
这道题我看每一个选项都有问题，后来退而求其次选了C，答案是A。
但我觉得A选项的reindeer have developed ，谓语和主语单复数不一致啊，reindeer从哪里看出来是用复数的，求NN解答，谢谢！