What type of support for a thesis completes the following statement? My thesis/topic sentence is true because

In a persuasive essay, normally in middle/high school, you have a topic and three main reasons to support it. And those three main reasons are in their own paragraphs.

So If you want to put "My thesis" it would work like this ...

My thesis is true because of (reason 1), (reason 2), and (reason 3).

Though wouldn't use My thesis because it doesn't have the "topic/prompt" of the essay/assignment.

Like if the prompt was

Should we do more to save trees? Yes or No? Why?

You could write

We should save more trees because (reason 1), (reason 2), and (reason 3).

Or

We shouldn't save more trees because (reason 1), (reason 2), and (reason 3).

Does this answer your question? Or no? Because your question was unclear.