Answer

A, B, C, D

Explanation

(a) Energy released
`( P) S_((g)) to S_((g))^(-) " " (S) N^(-) to N`
(electron removal is an exothermic process because electron addition is an endothermic process in this option)
(b)Energy obserbed
`(Q) O^(-) to O^(2-)" "` (inter electronic repulsion)
`(R )Sr to Sr^(2+)" "`(electron removal process of IP)
(c) Inert gas configuration
`(Q)" " underset(2p^(5))(O^(-))to underset(2p^(6))(O^(2-)), (R ) " "underset(5s^(2))(Sr) to underset(4p^(6))(Sr^(2+))`
(d) Half filled configuration
`(S)" " underset(2P^(4))(N^(-))to underset(2P^(3))(N)" " (T) " "underset(P^(2))(Ge)to underset(P^(3))(Ge^(-))`