"Calm down, Mrs. Blakely," Holmes replied. "The solution to this mystery is staring you in the face. There is no sign of a break-in, so the thief has access to the house. The thief disappeared in this spot without using the far door, so there must be a hiding spot within the walls or floor. There are scratches on the ground near this portrait. I felt a draft when I reached down to test the floor. It's elementary, Mrs. Blakely. The thief is hidden in the wall behind this portrait."

Holmes pushed the portrait harder into the wall. The wall moved, revealing a hiding place. Sherlock Holmes lit a candle. Its light revealed a sleeping maid with a gigantic purple gem clasped in her hands. The mystery of the disappearing thief was solved.

What do the details show about Sherlock Holmes' character?

A. He is too frustrated to solve the mystery.
B. He makes assumptions when trying to solve the mystery.
C. He only relies on his instincts to solve the mystery.
D. He uses clues and his skills to solve the mystery.