The correct answer is:
a. PPO insurance plans offer a wider choice of primary care doctors and specialists.
PPO (Preferred Provider Organization) plans generally have higher premiums than HMO (Health Maintenance Organization) plans because they offer more flexibility and a wider network of providers. Members of PPO plans can see any doctor or specialist without a referral and typically have coverage for out-of-network providers, although at a higher cost. HMO plans, on the other hand, usually require members to select a primary care physician and obtain referrals to see specialists, which can help keep costs lower and make premiums less expensive.