Answer: The right answer is the C) Integrity.
Explanation: Just to elaborate a little bit on the answer, it can be added that the word probity comes from the Latin adjective probus, which can be translated as "good" or "honest." Since the old man was considered incorruptible, he had the moral strength to refuse to do something wrong or incorrect. Therefore, he was known for his probity, or his ability to act with honesty, rightness, and integrity — this last word also comes from the Latin, specifically from the term intĕger, which means "intact" or "pure."