Answer: hello the options related to your question is missing hence i will provide an answer that fits into the blank.
answer:
In rapport or In harmony
Explanation:
The new actor on the set was so ____in rapport______ to every request that the director had not a single argument with him.
The actor did not have a form of argument with the director because they had an understanding hence the synonym of the word understanding that can fit into this context can be in rapport or In harmony
