Which explicit detail is best supported by this passage?

Using a mixture of purple and brown paints, Katrina paints a slender trunk and branches on the deep blue background of the canvas. Humming happily, she dips her brush into the green paint and taps it lightly around the branches, making dots that look like leaves. They are bright and cheerful against the blue sky.

A. Katrina enjoys painting.

B. Katrina is humming.

C. Katrina is painting a tree.

D. Katrina is in a painting class.

B. Is correct​