Hello Saloni, on the basis of 2018 last round cutoffs, you can get admission in B.A Hons in geology in Aditi Mahavidyalaya college(last round OBC cutoff 69%), B.A Hons in Hindi from Bhagini Nivedita college(last round OBC cutoff 54%) and Dyal Singh college(last round OBC cutoff 67%). there are many other colleges too where you can get admission. below is the link to the 10th cutoff list. have a look at it yourself and then finalize your college and course:

2018 DU Last round cutoff for B.Sc: http://www.du.ac.in/du/uploads/Admissions/Cut-off/2018/10th%20Cut-Off%20-%20Science.pdf

2018 DU Last round cutoff for B.A: http://www.du.ac.in/du/uploads/Admissions/Cut-off/2018/10th%20Cut-Off%20-%20Arts%20&%20Commerce.pdf

Yes

You can get seat in Delhi university for BA course under obc category in 5 to 6 cut off list maybe

Check the cutoff list and apply accordingly.