Answer:
Correct option is (a)
Explanation:
Unearned revenue are revenue earned against services that have not been performed yet. In accrual system, revenue is recognized when service is performed against it.
Revenue earned without service being discharged is treated as liability till the period service is performed. It is recognized as income only after service is performed. For example unearned rent revenue is an unearned revenue which is reported as a liability till the rent period for which revenue was received is over.