To find out which choice(s) is(are) feasible, let's look at a specific example: a = 2, b = 4, c = 8, p = 6, q = 3, r = 2 (a,b,c) = (2,4,8) are in geometric sequenceis satisfied because (p,q,r) = (6,3,2) are not in geometric nor arithmetic sequence. (p,q,r) = (6,3,2) are in harmonic sequence because their reciprocals (1/6, 1/3, 1/2) are (1/6,2/6,3/6) are in arithmetic sequence. (p2,q2,r2) = (62,32,22) = (36,9,4) are not in geometric nor in arithmetic sequence. This is a counter-example to all choices but C. So, A,B,D,E are disproved. So if we are given that one of the choices is correct, then that correct choice can only be C. But it is possible that "none of these" is the answer, although it is not listed. So we must prove that if (a,b,c) are in geometric sequence, and then (p,q,r) are in harmonic sequence, which means that is in arithmetic sequence. But as yet I have not proved it. Maybe Ikleyn or greenestamps can help. I'll keep working on it. Edwin