Atoms and Nuclei

(A) Mass number of the resulting nucleus is <100; thus, no change is B/A. Hence, no energy is released.
(B) Mass number of the resulting nucleus is between 100 and 200, then B/A thus increases. Hence, the energy is released and the resulting nucleus is more stable.
(C) The daughter nuclei has 50 < A < 100; therefore, B/A decreases. Hence, there is no release of energy and hence the stability also decreases.
(D) The daughter nuclei has 100 < A < 130; therefore, B/A increases and hence the energy is released and so is stability.