here is my reasoning..
i think C says something about the debate 2 centuries ago.. but i don't think that the debate is lss important or strong now than it was 2 centuries ago..
coz as per the opening sentence of the passage the debate is strong enough as the experts take part in it.......
so C is out..
E on the other hand says that it is an early expression of a central issue and i think that is true as per the second para and as per the last statement of 1st para..

D is incorrect b'coz it states the opposite of the passage..
passage says that neither side knows about the origin of this debate ..

hence E should be the correct answer.. and that is what the correct answer.. i just wanna confirm whether this is correct or is there any better explanation for this question..