The correct answer is smother.
D. breathe heavily
The correct answer is (A) To smother or suffocate; to cause to die or lose consciousness by impairing normal breathing, as by gas or other noxious agents; to cause asphyxia.
Asphyxiate comes from Greek asphyxia + ate. Greek a- (without) and sphuxis (pulsation).
Examples of use:
- The murderer used a pillow to asphyxiate her.
- The coroner advised that the victim had been asphyxiated.