The first ionization energies in eV of nitrogen and oxygen are respectively:

1. 14.5, 13.5
2. 13.6, 14.6
3. 13.6,13.6
4. 14.6, 14.6

it’s answer is A as first I.P. of nitrogen is higher than oxygen. it is because in nitrogen p-orbital is half filled as it contains 3 elecrons and in oxygen p orbital contains 4 electrons so it is niether half filled nor full filled. due to this it is harder to remove electron from nitrogen than oxygen as half filled or full filled orbital stablises resulting in increase in I.P. so answer is A i.e. 14.5 eV for nitrogen, 13.5 eV for oxygen