The correct answer is C. Figurative language
Step-by-step explanation:
Figurative language refers to the non-literal language, this implies figurative languages uses words and phrases in a non-conventional way, this includes the use of metaphor, simile, personification, onomatopoeia, and other literary figures.
The excerpt presented is a clear example of figurative language because it uses words and phrases in a non-conventional way, this can be seen in "like pale flags" that is an example of simile in which the author compares the curtains to flags to express how the move; also this can be seen in "the wine-colored rug" that the author uses to express the color of the rug, and it "as wind does on the sea" that uses comparison to describe the way the curtains form a shadow over the rug.