Use the excerpt from “An enemy of the people by Henrik Ibsen to answer the question. Peter’s accusation in line five that Dr. Stockmann investigated “behind my back” suggests which of the following?

Peter is paranoid he will lose his power
Dr. Stockmann does not trust his brother
Peter knows he is doing something immoral
Dr. Stockmann is obsessed with discovering the truth
The brothers will never agree on important issues

The excerpt does not provide enough information to determine the correct answer.