An insurer that has received authorization from the appropriate state insurance regulator to transact insurance in that state is an admitted insurer, also described as an authorized insurer. Authorization is evidenced through the regulatory authority granted to conduct specified insurance business within the jurisdiction.

The other choices describe different classifications. A domestic insurer is organized under the laws of the state in which the classification is being made. A foreign insurer is organized under the laws of another U.S. state. Either a domestic or foreign insurer may become admitted in Arizona if it meets the state ' s requirements and receives authority to transact insurance. A mutual insurer is classified by ownership structure: it is owned by its policyholders rather than stockholders. Mutual status does not, by itself, establish whether the insurer is authorized in a particular jurisdiction.

Accordingly, the decisive wording in the question is “authorized to do business in a state.” That points directly to admitted rather than domestic, foreign, or mutual.

Study Guide Reference: Insurance Regulation — insurer classifications; admitted/authorized versus nonadmitted insurers; domestic, foreign and alien insurers; regulatory authority.