Logic Gates question from JEE Main 2020 (8 Jan, Shift 1)

Answer: (c)

1. Switches with diodes from the 5 V supply act as an OR gate at the base: base high if A or B is closed.
2. Base high saturates the transistor, so collector (output) falls to 0; base low gives output 1.
3. $Y = \overline{A + B} = \overline{A}\cdot\overline{B}$ (NOR).
4. So the answer is (c).