Answer: Unearned subscription revenue.
Step-by-step explanation:
Tax is made on a cash basis which means that a transaction is eligible for taxation once cash has been paid for it. Businesses however have to use the Accrual basis which only record transactions in the period that they have been incurred.
In this scenario, there is more subscription payment in cash than the company recognized which means that the company has not yet delivered the service they were paid for and so could not recognize the subscriptions. They will however be taxed on those amounts because the cash has come in.
The account giving this temporary difference is therefore the Unearned Subscription Revenue account.