Mass numbers of the elements A, B, C and D are 30, 60, 90 and 120 respectively. The specific binding energy of them are 5MeV, 8.5MeV, 8MeV and 7MeV respectively. Then, in which of the following reaction/s energy is released?
(a) D→2B
(b) C→B+A
(c) B→2A