i think the answer is A
'inspiration for several of her mystery novels' looks weird..
may be 'inspiration for her to write several of her mystery novels'... would be better..
in my view, in any case ,E cannot be the answer
the answer has to be C ..
when p=140x and q is 7^n q will divide p only once .. that is 140/7.. other powers of 7 if any will remain so that the value of p= 20a.. so that is what is the value of R ... as 20 is divisible by 5 .. R is divisible by 5
i think the answer is B ...
A cannot be the answer because we are concerned with majority of the rats that are not affected by cancer and not with rats that are affected... we don't care about the substances that affect the rats or guinea pigs..