In the system shown in figure at some instant acceleration of pully was 10 m/sec2 in upward direction. At that instant spring was in its natural length. If acceleration of block A and B are aA and aB at that instant then :
(Given mA = 10 kg , mB = 20 kg , g = 10 m/sec2 , pulley is light and smooth)
(A) aA = 10/3m/sec2 upward aB = 10/3 m/sec2 downward
(B) aA = aB = 5 m/sec2 upward
(C) aA = aB = 10 m/sec2 downward
(D) of these