Read the excerpt from "Bone Detective."

Diane stood in front of a mirror and stuck out her tongue. It looked like a rosy pink welcome mat to her delicate insides. Her usual rubber mold formula was out of the question—too toxic. She wondered, What is safe to swallow, fast and easy to apply, and hardens quickly into a firm mold?

One of her horse-riding pals, a veterinarian named Mary Wright, had the alginate. Mary told Diane that alginate was a pink gummy material used to make molds of teeth. If it was safe for pets, it should be safe for a tiger.

And people, too, Diane thought.

At her lab she mixed the alginate powder with water to form a paste. Standing in front of a mirror, she scooped up a blob and spread it on her tongue. She pressed it down with her fingers to get out any air bubbles. Not bad, she thought. Tastes just like spearmint. She decided to make an extra-thick mold to make it easier to peel off. So, she added another gloopy blog—and another.

With her thickened tongue hanging out, Diane padded around the lab doing odds and ends while the material set. After about 10 minutes, she peeled off the alginate slowly and carefully. It was fragile—bendable and easy to tear—but it made an excellent impression of her tongue.

Which action in the excerpt illustrates that Diane is dedicated to her work?

A) She makes a mold of her own tongue.
B) She performs odd jobs around the lab.
C) She stands in front of the mirror.
D) She goes horseback riding with a friend.