Which of the following is the topic of Paragraph 3?A.Some historical documents may not be

Which of the following is the topic of Paragraph 3？

A．Some historical documents may not be real.

B．Some authors may not be honest.

C．Historians should be careful about their sources.

D．historians may be influenced by their own backgrounds.

请帮忙给出正确答案和分析，谢谢！