The correct answer is D. His father told him not to pull the dog’s tail.
Option A is incorrect because the father did not say that he did not pull the dog’s tail. He said not to pull the dog’s tail.
Option B is incorrect because the father did not forbid him not to pull the dog’s tail. He simply told him not to do it.
Option C is incorrect because the father did not tell him to pull the dog’s tail. He told him not to do it.
The sentence “Don’t pull the dog’s tail” is a command. It is a direct order from the father to his son. The son is being told not to do something. The father is using the word “don’t” to express his disapproval of the son’s actions. The father is also using the word “pull” to describe the son’s actions. The father is telling his son not to pull the dog’s tail.