Final answer:
The Waiver of Premium Rider is added to a life insurance policy to prevent it from lapsing if the insured becomes totally disabled and can't pay premiums.
Step-by-step explanation:
The rider that can be added to a life insurance policy to ensure that it does not lapse if the insured is totally disabled is known as the Waiver of Premium Rider. This type of rider allows policyholders to maintain their current life insurance coverage without having to pay the premiums if they become totally disabled and are unable to work. This way, a policyholder's insurance protection remains in force, even if their ability to pay premiums is compromised due to their disability.