If a1b+1c,b1c+1a,c1a+1b are in A.P., then
a,b,c are in A.P.
a,b,c are in G.P
a,b,c are in H.P.
none of these
a1b+1c,b1c+1a,c1a+1b are in A.P
⇒a1b+1c+1,b1c+1a+1,c1a+1b+1 are in A.P
A.P
⇒abc+ca+ababc,bbc+ca+ababc
cbc+ca+ababc are in A.P
⇒a,b,c are in A.P