I'm pretty sure it may be answer B)
Answer: C
C3 carbon fixation is more common in areas with high light intensity than C4 carbon fixation.
Answer = C
The hyphen (dash) does not need to be placed anywhere in that particular sentence, but it can be placed between "inner" and "city". You do however require commas in the sentence; "Basketball, which has long been thought to be an inner city game, is extremely popular in the suburbs."
