Nigel has been chosen to moderate the class discussion about The Diary of Anne Frank. He knows that his
classmates have very strong opinions about the book and he is worried that the discussion may veer off track
When this happens, he needs to be prepared to
speak loudly to command everyone's attention.
add his own opinion whenever he feels like it.
review the ground rules and then ask’a new question.
sit silently and wait for the group to redirect itself.

Speak loudly to command everyone's attention or add his opinion.

Explanation:

Reason why i say this is because

1.  Adding his own  would cause a fight unless the group is calm about things like that.

2. Reviewing the ground rules is dumb everyone has a strong opinion about something so it not that

3.Sitting and waiting takes while since people fuss take long plus someone might drag him into the fuss, but i might be wrong

(sorry if you got it wrong T>T)

abruptly

i think the best answer would be d allowing 30 seconds between response would give time for what was already said to sink down in your mind.