Correct Answer: An attitude of moral superiority

Solution : The third option is the correct choice.

The idiom on one's high horse or get off one's high horse is commonly used to convey an attitude of moral superiority. When someone is said to be on his high horse, it suggests that he is behaving in a self-righteous or condescending manner, looking down on others.

Therefore, the correct answer is, an attitude of moral superiority.