Intangible assets that have an indefinite useful life:
a. Are those whose acquisition costs is not amortized over their useful life.
b. Are those with no legal, contractual, or economic factors that are expected to limit their useful life to a company.
c. Are those with no foreseeable limit on the period of time over which the asset is expected to contribute to the cash flows of the entity.
d. All of these answer choices are correct.