When are commas necessary to include with numbers?

What causes cassius to delay killing caesar? a. the crowds around caesar b. a violent storm c. brutus’s reluctance d. the disorganization it the resistance

In the conclusion of the radio broadcast war of the worlds, orson welles:

Read the excerpt. “this is a train-servicing station and we have to wait for a train.” he shakes his head. i smile. “it’d be nice if we could get one.” lauren mizock has revised her draft of “train tracks” to convey plot events using