In the following question, there are six sentences marked S1, S6, P, Q, R, S. The positions of S1 and S6 are fixed. You are required to choose one of the four alternatives which would be the most logica passage.

S1. He tried to open the door.

P: The room was neat and clean.

Q: Then he stepped into the room.

R: He waited for a minute or two.

S: It opened easily and he peeped in.

S6. He was careful not to touch anything.