question_answer

If \[\frac{1}{\sqrt{b}+\sqrt{c}},\frac{1}{\sqrt{c}+\sqrt{a}},\frac{1}{\sqrt{a}+\sqrt{b}}\] are in A.P., then \[{{\pi }^{ax+1}},{{\pi }^{bx+1}},{{\pi }^{cx+1}},x\ne 0\]are in

A)  G.P.           

B)  G.P. only if x < 0

C)  G.P. only if x > 0

D)    None of these