Which of the following best describes a thesis statement?

A. sentence that presents a subject and makes claims about it to be proven later

B. the last sentence of an introduction

C. a sentence that states an opinion

D. none of the above

The correct answer is A. sentence that presents a subject and makes claims about it to be proven later

It is usually found at the end of an introduction but this is not obligatory and can sometime be found earlier. It does often state an opinion but it is not obligatory either.