Can someone plz help me with this!

After "late".

Unless the caterer is late, this banquet should go off without a hitch.

Explanation:

If you read this sentence out loud, you would give a slight pause after "late", indicating a comma.

Hope this helps!

an important event in the author’s life

Option C.

Explanation:

The passage given in the question has been taken from "Ellis island" which has been written by Barbara Davis Pyle. It is about an important event in the life of the author which speaks about when the author along with his parents crossed the harbor of city and entered the United States of America.

This was the event of starting a new life by the author with his family. This it was one of the major and happy events.