People seem to think that the pyramid workers were slaves, which is ridiculous and untrue.
The tone of the original passage is formal. It could be in a trusted, reliable source on Egyptians. The answer has an informal tone. It uses the words "ridiculous" and "untrue". These opinion words make the sentence of opinion not a statement of fact. The original sentence is a statement of fact.
It uses logical examples and explanations to examine a topic in an organized way.
An expository essay is an essay in which the author makes a statement about a topic and then backs up his/her reasoning with specific examples and explanations. The examples and explanations should be logical and organized in a way that makes it easy for the reader to see how the author builds support for his topic.
The other options apply to other forms of literature. A play uses dramatic elements. A poem uses poetic techniques. A story uses narrative techniques.
I believe that is an imperative sentence because it is giving a command.