Staements I: Light nuclei are most stable if N =Z, while heavy nuclei are more stable if N gtZ. (N`rarr` number of neutrons, Z`rarr` number of protons)
Staements II: As the number of protons increases in a nucleus, the Coulomb's repulsive forece increases, which tends to break the nucleus apart. So, to keep the nucleus apart. So, to keep the nucleus stable, more number of neutrons are needed which are neutral in nature.

Answer

a

Explanation

Here,both the statements are correct and Statement II correctly explains Staement I.