Final answer:
The management assertion regarding account balances at the period end is that the entity holds or controls the rights to assets, and liabilities are obligations of the entity.
Step-by-step explanation:
Option C, 'The entity holds or controls the rights to assets, and liabilities are obligations of the entity,' is a management assertion regarding account balances at the period end.
This assertion ensures that the entity has legal ownership or control over the assets reported in the account balances and that the liabilities reflected in the account balances are indeed obligations of the entity.
For example, in a T-account for a bank, the assets side would include the bank's reserves and loans made by the bank, while the liabilities side would include the deposits made by customers. The management assertion in option C affirms that the bank has the rights to these assets and that the liabilities represent the bank's obligations to its customers.