Thewith sharingkeyword ensures that the Apex class respects the sharing rules of the current user, including private sharing models. This means the logged-in user will only see records they own or have been shared with them.
Reference:Apex Class Sharing Rules
Incorrect Options:
B:without sharingignores sharing rules, exposing data the user does not have access to.
C:Filtering withUserInfois not a scalable or maintainable solution.
D:Schema describe calls do not enforce sharing permissions but only check object-level access.