Select all that apply. Which of the following statements is (are) correct regarding unearned revenues?
a. Unearned revenues are amounts owed by customers for services performed.
b. Unearned revenue refers to a liability that is settled when a company delivers a product or performs a service.
c. Unearned revenue is a liability account which is set up when a customer pays in advance for a product or service.
d. Unearned revenues refer to assets which have yet to be billed to customers for services performed by the business.