Michael Chang receives health care services through a health maintenance organization (HMO) offered by his employer. One characteristic that distinguishes the HMO from other forms of managed care plans is that it

a. requires Mr. Chang to receive services from network providers in order for the services to be eligible for benefits

b.requires Mr. Chang to pay both a deductible and coinsurance amount for all services he receives

c. allows Mr. Chang to decide, when he needs medical services, whether to seek services from in-network or non-network providers

d. allows Mr. Chang to receive services from specialists without a referral from a primary care provider (PCP)