Select the correct indirect form of the given sentence.“You must work hard to succeed in your new venture”, said the mother to her son.

• A. The mother ordered her son to work hard to succeed in his new venture.
• B. The mother requested her son to work hard to succeed in his new venture.
• C. The mother pleaded her son to work hard to succeed in his new venture.
• D. The mother advised her son to work hard in order to succeed in his new venture.