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)
Ruby negi
use the same concept for finding distance of Point P from charges on y axis.. try to do it by urself too... good luck for any doubt you can ask.
but answer is D
solve complete..you will get answer..