Energetics of Nuclear Fission

Q. Assume a hypothetical nuclear fission reaction:
$X\to Y+Z$
If the atomic masses of $X,YandZ$ are respectively $x,yandz$ calculate the maximum amount of heat generated if 1gramof X undergoes fission. Consider the molar mass of X to be M.

1. $\frac{N_A}{M}\times (y-z-x)c^{2}units$
2. $\frac{N_A}{M}\times (x-y-z)c^{2}units$
3. $\frac{N_A}{M}\times (x-y+z)c^{2}units$
4. $M\times (x-y-z)c^{2}units$

Q. A heavier unstable nucleus breaks into two fragments of comparable mass in a nuclear fission reaction and energy is released because:

1. The total rest mass energy of the two fragments is less than the rest mass energy of the heavy nucleus.
2. The binding energy per nucleon of the two fragments is more than the binding energy per nucleon of the heavy nucleus.
3. The nuclei of the fragments are more bound than the nucleus of the parent.
4. NONE OF THE ABOVE