Which of these is an example of chemical weathering's changing the appearance of a rock?

A: Sand blown by the wind scrapes against the rock, which over time breaks apart the rock.
B: A plant grows in the crack of a rock, and over time the plant's roots break apart the rock.
C: Carbon dioxide dissolves in water to create carbonic acid, which over time dissolves the rock.
D: Water freezing in the crack of a rock causes the crack to become larger, which breaks apart the rock.