SEBC reservation is for socially and economically backward whose income is less than 8 lakhs per annum. And as this reservation is given at State Leve, you do not have this option in NEET application form. So please select OBC-NCL as your Category if your annual income from all sources is less than 8 lakhs per annum. But if it is more than 8  lakhs per annum, you have to select General Category and while filling Maharashtra State Counselling form, you ca select SEBC.