Time management is very much important in IIT JAM. The eduncle test series for IIT JAM Mathematical Statistics helped me a lot in this portion. I am very thankful to the test series I bought from eduncle.
Nilanjan Bhowmick AIR 3, CSIR NET (Earth Science)
Suman Kumar
For such question. Remember this two MO diagram
If eletron sum is less than or equal to 14 then use MO of nitrogen.
If eletron sum is greater than 14 then use MO of oxygen.
Now fill the eletron according to aufbau principle.
Now you can solve the question.
If you still need help then I will send the solution