A plot of the number of neutrons ( N ) against the number of...

As $\dfrac{N}{P}$ ratio is less than $1$, for possible decay mode, $\dfrac{N}{P}$ ratio should increase. The possible modes are $\alpha$-decay, K-capture and ${\beta}^{+}$-decay. Hence, the correct options are \left(2\right) and \left(4\right) (In ${\beta}^{-}-decay or$neutron decay, \dfrac{N}{P} ratio will decrease further).
\dfrac{N}{P} s$hould increase. So,<br />${}_{0}{e}^{- 1} + p 11 ⟶ n 10$[K-electron Capture]<br />$p 11 ⟶ n 10 + \beta 01$[${\beta}^{+}-decay]