Select the most appropriate direct form of the given sentence.He regretted the mistake he had made in his calculations.

• A. He said, “I regret the mistake I made in my calculations.”
• B. He said, “He regrets the mistake he made in my calculations.”
• C. He said, “I regretted the mistake I made in my calculations.”
• D. He said, “I am sorry for the mistake I made in his calculations.”