The correct answer is A) he begins to consider illogical possibilities.
Mr. Utterson develops in these excerpts by beginning to considerate illogical possibilities.
This is so because Mr. Utterson says in excerpt 1, “This is a very strange tale, Poole, this is a rather wild tale mu man”. And he is bitting his finger is a nervous mode, considering illogical possibilities. The same happens in excerpt 2, when he adds: “No sir, that thing in the mas was never Dr. Jekyll. God knows what it was, but it was never D. Jekyll.”
The excerpts are taken from chapter 8 of “The Strange Case of Dr. Jekyll and Mr. Hyde”, is a novel written by Robert Louis Stevenson.