Which of the following statements about preferred provider organizations $($PPOs$)$ is true?

Employees who participate in a PPO are required to use the plan's providers exclusively.

All of the above statements about PPOs are true.

Companies with at least $25$ employees who live in a PPO service area are legally required to offer membership in the PPO as an alternative to regular group health coverage.

Employers like PPOs because they are highly regulated.

Employers contract with health care providers to deliver discounted services to participants.