Revise incorrect sentences (analysis)

Choose C

A: There is no subject. We know from a large number of observational facts that in order to grasp the continuous changes of weather, it is best to make observations every hour.

B: Repeated statements. The three competition classes of physics, biology, and chemistry held by our school won the national second-level, provincial first-class, and municipal first-class awards

D: Repeated sentences.

There are fruits all over the mountains and plains: pears, apples, persimmons...