Which of the following is true about problem-and-solution essays?

They are a type of expository writing.

They are only written in classroom settings.

They are the most common type of writing prompt required of students.

The first statement is true. Problem-and-solution essays are a type of expository writing that discusses a problem and proposes a solution to it. The other two statements are not necessarily true, as problem-and-solution essays can be written in various settings and are not always the most common type of writing prompt required of students.