What does the word 雨(yŭ) in this sentence refer to?

Beginner Level 初级 (chūjí)
“这些天, 西安一直在下雨(Zhè xiē tiān, Xī’ān yìzhí zài xiàyŭ ).” What does the word 雨(yŭ) in this sentence refer to?
A. Wind
B. Sun
C. Rain
D. Moon