By which law is the energy produced in a nuclear reaction given?

Match List-$I$ and List-$II$ and choose the correct option using the codes given below:

List-$I$ (Nuclear reactor component)	List-$II$ (Used substance)
$1$. Moderator	$(a)$ Uranium
$2$. Control rods	$(b)$ Graphite
$3$. Fuel rods	$(c)$ Boron
$4$. Coolant	$(d)$ Lead
	$(e)$ Sodium

The activity of a radioisotope changes with:

In a fission reaction,the nucleus of an element:

If the amount of radioactive substance is increased three times and simultaneously the temperature is also increased three times,the number of atoms disintegrating per unit time would be

Stable nuclides are those whose $n/p$ ratio is