GMAT Sentence Correction (SC) | A march 2000 census bureu survey showed that mexico

Hey Sayantanc2k,

This question has been discussed in mulitple posts. I am having trouble understanding why A is wrong. I read a few explanations and none of them were that convincing. Can you please clarify what choice A intends to say versus what choice B intends to say?

Thanks,

Humam

https://gmatclub.com/forum/a-march-2000 ... fl=similar