XAT

MAT is easy, but there are only 1 or 2 colleges, which accepts MAT score.
All the best.

It's your wish.
CAT, MAT, XAT, SNAP, and NMAT are few of them.
Almost all the colleges accept MAT except IIMs, Xavier's, Symbiosis, and NMIMS. You need to qualify entrance exams like CAT, XAT, SNAP, or NMAT to get admission in IIMs, Xavier's, Symbiosis and NMIMS.
MAT is enough if you wish to apply for other good colleges.

Yes, you can appear for national level management entrance exams, but even if you score good marks in the CAT, MAT or XAT exam, you won't get admission in any of the B-schools. You will have to clear your backlogs, first.

TIME Institution's study material notes are the best if you want to focus more on quantitative aptitude and data interpretation.

Give Maximum mock tests and you should solve the best questions of your choice. Maintain your question-solving speed. Keep rectifying your mistakes and practice as much as you can.

You should mainly focus upon Quantitative Aptitude and Data Interpretation, Following by Logical Reasoning. Try to give small mock tests on individual sections every week. After two months of preparation, start giving complete mock test 5 times a month.

If U think that As Your Wish

Dear Abhinav Prakash, for XAT exam you can follow as: For Quant, I recommend Quantum CAT by Sarvesh Kumar. Topics are explained reasonably well and quality of questions is also very good.
Sentence Correction and Critical Reasoning guides from Manhattan GMAT.
and you can practice previous question papers.
All the Best.

The selection is done by interview panel. If the resume is acceptable and the reasons for the percentage is justifiable enough then you may be able to make it.