Which of these post secondary degrees comes after a master's degree?

Answer: Doctor's degree.

Explanation:

A doctor's degree is a diploma issued by universities. It is the highest Academic title that can be won at a university. In most countries, this diploma is valid after a particular scientific thesis is defended, and the candidate has the skill to teach at the highest academic level. In the United States and some other countries, there are also some types of technical or professional degrees that include doctors on their behalf and are classified as doctors in some of these countries. Some universities also award honorary doctoral degrees to contribute to the university, science, or community.