The correct answer is C. Mr. Pontellier's opinions offend his father-in-law.
Explanation
According to the extract, it can be inferred that Mr. Pontellier's opinions offend his father-in-law because this is explicitly expressed in the statement when he says "He made an effort, in a general way, to express a particular disapproval, and he only managed to arouse the anger and opposition from his father-in-law. " Furthermore it can be inferred that Mr. Pontellier's opinions cause anger in his father-in-law because he was against horse racing unlike his father-in-law as expressed in this excerpt "Mr. Pontellier himself had no particular inclination towards horse racing, and even more like discouraging it as a hobby. " Therefore, the correct answer is C. Mr. Pontellier's opinions offend his father-in-law.