Or is it c? How does your text distinguish between these two?
Actually, the correct answer is c. testimony. Testimony refers to the use of personal accounts or statements from individuals who have firsthand experience or knowledge of a particular situation. In this case, Mandy is using the information provided by the source she interviewed about the illegal treatment by the police. By including this source's account in her speech, Mandy is using testimony to support her argument or present a specific perspective on the issue.