See the rules for writing the MCQ answers in the answer sheet is that you should mention the option number followed by the answer. As you have put only the answer, the teacher may deduct partial marks but it won't be marked entirely wrong. You must be very careful with this things, because the deviations in total marks at board level examination are mostly for this kind of silly mistakes. Don't worry you will get marks, but its dependent on the teacher whether the marks will be deducted or not.

For more information regarding HSC you can consider the link below:

https://school.careers360.com/exams/maharashtra-hsc-board

I hope this helps. Wish you a great day!