Correct Answer - D
pth,qth,rth terms of A.P. are
a+(p-1)d=x (1)
a+(q-1)d=xR (2)
`a+(r-1)d=xR^(2)` (3)
where R is common ratio of G.P.
Subtracting (2) from (3) and (1) from (2) and then dividing the former by the later, we have
`(q-r)/(p-q)=(xR^(2)-xR)/(xR-x)=R`