Hi Brad,
Provided Persons C-J each has their own Work License, if Person B is a SysAdmin, they could "Log In As" Persons C-J (in succession) and enter the time for those folks just as if they'd done so themselves, as far as auditing goes.
On the other hand, if Persons C-J have only Reviewer Licenses, or Person B is not a SysAdmin, I invite you to consider our UberTimesheet solution, which we would configure for you so Person B could then use to select Persons C-J from a dropdown and then enter the time "on behalf of" those folks, as far as auditing goes (e.g. "Person B entered 2 hours on behalf of Person C"), which, arguably, is also a better representation of the facts.
Regards,
Doug