Final answer:
The main idea in Ted Chiang's 'Exhalation' is the inevitability of death, as it explores the nature of existence and the finite quality of the universe.
Step-by-step explanation:
The main idea in Ted Chiang's "Exhalation" is A. the inevitability of death. The story explores themes of existence, the flow of time, and the nature of the universe, culminating in the recognition of death's inevitability. Through a mechanical narrator who examines its own functioning and realizes the finite nature of its world, Chiang reflects deeper philosophical questions about the end of existence and the value of the time we have.