Final answer:
The term for armpit is 'Axilla,' so the answer is A) Axilla.
Step-by-step explanation:
The word for armpit is Axilla. Therefore, the correct answer is A) Axilla. The other terms listed refer to different parts of the body: B) Rectum is part of the lower digestive system, C) Tympanum is another word for the eardrum, and D) Temporal relates to the temporal bones on the sides of the skull.