Answer:
C. Foil
Step-by-step explanation:
Wei-Chen is not the protagonist of the story. Nevertheless, he is a very important character. Wei-Chen is Jin's best friend, and he also acts as Jin's foil. The characteristics of Wei-Chen serve the purpose of highlighting the characteristics of Jin by contrast. Wei-Chen is a loyal, kind friend, and he is extremely supportive of Jin. He is also instrumental in Jin's success with Amelia.