Which sentence below correctly refers to the collective noun troop as a whole unit? a. the troop are marching down the hill to a shady spot to rest. b. the troop is marching down the hill to a shady spot to rest. c. the troop are planning to change their shoes while they rest. d. the troop have to raise at least $500 each in order to be able to attend summer camp this june.

Read the sentence. marissa heard the class bell ringing loudly walking down the hall. what is the best way to revise this sentence? `marissa heard the hall ringing loudly walking down by the class bell. `marissa heard the class bell walking down the hall ringing loudly. `walking down the hall, marissa heard the class bell ringing loudly. `walking down the hall, the class bell ringing loudly marissa heard.