Answer:
The student read a new book.
Many students protested the new uniform requirement.
The peacemakers signed a new agreement.
These sentences are written in an active voice because the subjects do the action.
(e.g the student does the action of opening a book, the peacemakers did the action of signing an agreement).
In the sentences written in a passive voice, the subject doesn't do the action, but the action is reflected on it(e.g. The books are not doing the action of opening, but they're being opened by the students, the papers did not sign theirselves, but they were signed by 20 representatives)
Answer:
The fourth choice: They are no longer comfortable around him
Explanation:
Charlie mentioned changes in how his coworkers intraced with him after his operation. They avoid him, they seem easily frightened by him, they don't talk to him much, and they don't rag on him like they did in the past right after his changes.