Which sentence uses the underlined words incorrectly?

A$.$ The flowers that appeared in the yard this year look vaguely similar, but the differences among them are so great that they couldn't possibly be from the same plant.

B Some species of tropical fish contain a certain toxin that if ingested, can interfere with a person's ability to sense the difference between hot and cold.

C The camp staff meeting was derailed by a difference of opinion that resulted in a long. drawn$-$out discussion ahout the faimess of the camp's behavior policy.

D Since we started feeding him on a schedule, there has been a difference about the cat's behavior.