Actually, yes, this is true. Let's look at some examples with the word "all" to see if it agrees with verbs in singular or in plural:
All is lost
All is well
All is arranged already.
All of it is nice
This shows us that "all" agrees with verbs in singular form: the correct answer is a) True.
He feels that people will make fun of him or he will feel left out.
Answer: They answer is 100% B. nostalgic
Explanation: Hope this helps!!!!!
I think the answer could be c or d. D makes a little more sense though. I hope this helps a little bit.