Question

People who abstain from eating any animal Foods may become deficient in. NOT VITAMIN C.

Answer 1

I would say they lack protein, because meat is the main source for protein in a persons diet, and if thats taken away then you have to find new ways to get that protein back. Like with eggs and nuts, etc. 
-hope this helps :3

Answer 2

I think the answer id D: Folic Acid