Hello Shikha

In order to take the GATE exam, you have to have to have a graduation degree of at least four years.

In your case: B Sc. (Research)/ B.S.- Bachelor’s degree in Science (Post-Diploma/ 4 years after 10+2)

So it is has to be either B.Sc Research or if you have done BS from IISER, then you will be eligible to write the GATE exam.