Question

it is said that in ___ china, doctors were paid when their patients were well.

Explanation:

We need to choose the word that fits the context of "in ____ China" to describe a time period when the doctor - payment practice occurred. "Ancient" means belonging to a time long past, especially in history, and it makes sense to say "in ancient China" to refer to the historical period when such a practice might have existed. "Doubts" is a noun or verb related to uncertainty, "relying" is a verb form (rely on), "clumsy" means awkward, and "heritage" is a noun referring to traditions or inheritance, so they don't fit the blank.

Answer:

D. ancient