You can consider below books -

A Comprehensive Guide for MCA Entrance Examinations by RS Aggarwal

A complete study package MCA Entrances of all Indian universities (Old Edition)

Excel With Objective Book For NIMCET By J B Dixit, Ruchi Sharma, Ashish Mangal

Arihant MCA Entrance Test (Self Study Guide) By Amit M. Agarwal

JNU -

There are no such books for JNU as it is advisable to visit book store near JNU as they sell handwritten notes along with some question papers.

Good Luck!!!