This is your idea. You won't take the exam. In fact, both statements are correct.

People are the main body, mainly to distinguish animals, plants and so on. Only man can transform nature through practice and form a social history, which is also material, and man is the main body.

To say that people are the main body of social history is to highlight that people are the main force to create history, which distinguishes some individuals (refuting the view that heroes create history) from those who hinder the development of history (progressive people are called people).

So don't worry about this. If you really have to choose one, of course, the textbook will prevail.