alex.gellatly wrote:Most of the purported health benefits of tea comes from antioxidants - compounds also found in beta carotene, vitamin E, and vitamin C that inhibit the formation of plaque along the body's blood vessels.

C) come from antioxidants - compounds also found in beta carotene, vitamin E, and vitamin C, and
D) come from antioxidants - compounds that are also found in beta carotene, vitamin E, and vitamin C and that
OA is D, what is wrong with C? Thanks

The original sentence intends to convey 2 things:
1)COMPOUNDS ALSO ARE FOUND IN carotene, vitamin E, and vitamin C
2) THAT INHIBIT formation of plaque along vessels

C) Compounds ALSO found in carotene, vitamin E, and vitamin C, AND INHIBIT..

here, COMPOUNDS ALSO found..., AND (also) inhibit. Issues here is:
a) ALSO changes the initial meaning - original sentence does not says that COMPOUNDS ALSO inhibit
b) COMPOUNDS FOUND (IMO we require a passive voice here, ACTIVE "FOUND" means COMPOUNDS DO THE FINDING on their own, but logically compounds are found by someone else. Therefore ARE FOUND is beter than FOUND)

D) presence of THAT AVOID any ambiguity about ALSO and makes it very clear that ANTIOXIDANTS are COMPOUNDS that DO two things: (1) FOUND in X.., and (2) INHIBIT. The presence of THAT clears any doubt about the 2nd phrase (inhibit...) with regard to whether INHIBIT is parallel to FOUND and attached to COMPOUNDS ALSO or just COMPOUNDS