What provides an additional death benefit for death due to any cause, accident, or illness?

The additional death benefit for death due to any cause, accident, or illness is best covered by the accidental death benefit rider. This rider specifically provides a greater payout in the event of death resulting from an accident, and while it can supplement the base death benefit, it does not replace it. The standard term rider, which you selected, generally refers to a temporary extension of life insurance coverage for a specified period, without the additional benefits tied to accidents or illnesses.

The cost-of-living rider adjusts the policy's death benefit in line with inflation, ensuring the coverage retains its purchasing power over time but does not specifically pertain to circumstances of death. The return of premium rider allows policyholders to recoup some or all of the premiums paid if no claims are made during the policy term. However, this feature does not provide an additional death benefit based on the cause of death.

Thus, the correct answer revolves around the specific nature of the accidental death benefit rider, which is designed to provide an additional payout for unexpected and tragic incidents, ensuring the insured receives extra financial support in those unfortunate circumstances.