The reletive clause starts after gmatclub so both that and which can be correct but out of more than and greater than more than is correct idiom here.
so we are down to A,C,D
since first part of the sentence is dependent clause,,the very next must be dependent in order to prove no run on error.from that prospective the second comma should not be their ,but with THAT it doesn't count as per grammar.dont think the second comma is a modifer part ,it's the main clause of the verb.so which will be required in such case so C,D now
IN C their is parralrllism error,it should have been information starting from x to y .in C you need to observe that way.
down to D
but it's not an official questions type I Guess.