Answer:
Characterization.
Step-by-step explanation:
Characterization is a literary device that an author or writer uses to describe a character's trait and feature. A writer would usually introduce a character through direct characterization and indirect characterization.
In Direct Characterization, the author directly tells the trait or personality of the character.
In indirect characterization, a character is described by revealing his/her personality.
In the given case, the author has used the device of characterization to describe the girl indirectly through her looks.
So, the correct answer is characterization.