I am unfamiliar with that vine, honestly. The name Vine gives me nostalgia- what a throwback!
It’s probably the first one hopefully you will get it
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.
You don't know their backround
you don't know how they act (ex: if they are disabled)
you don't know what their status is (ex: if they are poor)
hope I helped you out