Which sentence fails to use correct parallel structure?
A) Please show respect by standing, being silent, and listening carefully to the speaker.
B) The bus that broke down was filled with expectant mothers, babies, and a few smaller children.
C) The teacher said we could use newspapers, magazines, encyclopedias, or websites for our research.
D) If you want to train well, you need to work on your rowing, hiking, biking, and of course you need to run more.
