for 15 years,the united nations has been ___"world water day"

题目

for 15 years,the united nations has been ___"world water day"
A congratulating B inspecting C observing D watching
the answer is C.TELL ME WHY

答案

15年来,联合国每年都庆祝“国际水节”.
C observe:庆祝、纪念,用于庆祝节日,和celebrate相当
A.congratulate 祝贺,一般是祝贺某人或某人的喜事
B.inspect 检查、审查
D.watch 观察
不明白的再问哟,望及时采纳,多谢!