Select the branch in which you want to pursue your career. All the three colleges are equally good. Still IT at MNNIT Allahabad would be best option for you.

Hey Shubham 

Why are you  even confused in your branches ? Look , a branch with better placements at a better college can even prove bad to you if you typically find no interest in it . So , firstly choose one branch only , in which you have your interest either IT , CSE or Chemical . After that , compare the colleges in that branch . You can compare the colleges using the following link : https://www.careers360.com/compare-colleges

Or , just mention your most interested branch out of these three , then i will tell you the best college out of these three for you.

Best of luck.