Which of the following is a basic feature of defined benefit (DB) plans?

A fundamental feature of defined benefit (DB) plans is the existence of vesting and early retirement benefits. In these plans, employees accrue a promise of a specified benefit upon reaching retirement age, which is often calculated based on factors such as salary history and years of service. The vesting feature ensures that employees earn the right to their benefits even if they leave the company before retirement age, typically after a certain period of service.

Additionally, DB plans often provide options for early retirement, allowing employees to retire before the standard retirement age with some potential adjustments to their benefits. This aspect distinguishes defined benefit plans from other types of retirement plans, where benefits may not be guaranteed or where employees have more control over investment choices.

The options referring to investment control by employees or an opt-out provision are not characteristic of DB plans, as they provide a defined benefit managed by the employer rather than individual investment choices. Additionally, while guaranteed returns might be applicable in some contexts, the hallmark of DB plans is the guaranteed benefit rather than the guarantee of returns on investments, which may vary based on the plan's investment performance.