The correct answer is D. Public speaking is a skill.
A skill is a learned ability to carry out a task with predetermined results often with the minimum amount of time, energy, or both. Public speaking is the ability to communicate effectively with a group of people. It is a skill that can be learned and improved with practice.
Option A is incorrect because public speaking is not a group of skills. It is a single skill.
Option B is incorrect because public speaking is not something that people have. It is something that people learn.
Option C is incorrect because public speaking is not something that people have. It is something that people learn.
I hope this helps!