Answer:
b. when a service has been performed or products have been delivered to customers without regard to when cash is received
Explanation:
In accrual accounting, revenues are recorded in the moment that the event that leads to them takes place, whether cash is received immediately after, or not.
In fact, the term accrued revenue defines revenue from a sale that has been completed but not yet received in cash.
For example, if a pizza delivery company sends 100 pizzas to a customer, but the customer will pay a month after, the revenue is still recorded in the accounting journal even if it the cash will only flow a month later.