Question

What does a speaker do when she justifies an opinion?

Answer 1

Evidence to support his point

Answer 2

I would say the correct answer is D. The speaker uses evidence to support her point of view.
If you want to justify your opinion, that means that you need to provide some proof in order to support your ideas. Nobody is going to believe what you are saying unless there is enough evidence to persuade them that what you are saying is true.