Q 11: Fundamental Rights - A Twist

Dude, this question is literally killing us. Our friend Rishabh and I got into a heated debate over this one in our study group. Here's how we're stuck:

Q. Under Art. 21 of the Indian Constitution, which one of the following is not protected? a) Abatement of the right to life b) Forced sterilization for the sake of national population control c) Death penalty in a rare case of a heinous crime d) Arrest without trial in an emergency situation

Mujhe lagta hai (I think) option b is the right answer, but Rishabh says a) or c) could also be the correct choice. Our professor also mentioned something about the 'public interest' clause, but it's all too confusing now. Can you guys help us out? Which one is the correct answer?