John and Bob had been friends since( kindergarten because he was good at soccer) and ready to laugh at any joke.
A .kindergarten because he was good at soccer
B. kindergarten because they were not only good soccer players
C.kindergarten because each was good at soccer
D.kindergarten,being not only good soccer players
The answer is C. Whyy? Can someone please explain why the answer is C and not D thanks in advance 
“not only” must eventually be completed with a “but” (or possibly a separate clause introduced with a semicolon). So that eliminates B and D both.
“Each” is the ideal subject here because it refers back to a plurality of things (“John and Bob”) but makes a point about each member considered separately.
thanks for the prompt reply
I forgot to write the last option “E” which was “kindergarten, they were both good at soccer” why is E incorrect?
“they were” is the beginning of an independent clause. Two clauses need to be joined with a conjunction or semicolon, not just a comma.