which sentence contains an error of agreement

the water was clear, blue, and beautiful

at first I stepped over the garbage on the street, but then I went back and picked it up

Pilots spend many years of their lives in training

He don't know what he's talking about

Verified Answer :

The last sentence is wrong, it has bad grammar

The first sentence says that the water was clear and blue, but you can't have water that is both clear and blue. It must be one or the other.