In which of the following oxides of three elements $$X, Y$$ and $$Z$$ are correctly arranged in the increasing order of acidic nature. The electronic configurations of $$X, Y$$ and $$Z$$ are $$[\mathrm{Ne}] 3 s^2 3 p^1, [\mathrm{Ne}] 3 s^2 3 p^5$$. [Ne] $$3 s^2$$ respectively

Assertion (A) 16 th group elements have higher ionisation enthalpy values than 15 th group elements in the corresponding periods.

Reason (R) 15 th group elements have half-filled stable electronic configurations.

Assertion (A) Fluorine has smaller negative electron gain enthalpy than chlorine.

Reason (R) The electron-electron repulsion is higher in chlorine than in fluorine.