Question

Which sentence is correct??

A. Has everyone bought their stapler?
B. Neither of the girls brought their book to class
C. None of the glasses were in its place.
D. Some of the children forgot their notebooks

Answer 1

There has to be a pronoun-antecedent agreement for the sentences. 

The correct sentence is D. Some of the children forgot their notebooks
"Some children" is plural and so is "their." 

It's not A because "everyone" is a singular indefinite pronoun and "their" is plural. 
For B, "neither" is singular and "their" is plural. 
And for C, "none" is singular and "were" is plural.