If the system of linear equations <br> $\; \; \; \; x +2 ay + az = 0$ <br> $\; \; \; \; x + 3by + bz=0$ <br> $\; \; \; \; x +4cy +cz = 0$ <br> has a non-zero solution, then $a, \; b,\; c$:

Question

( A ) are in AP
( B ) are in HP
( C ) are in GP
( D ) satisfy $a +2b +3c =0$