Which rider allows the wife of the insured to be added to the primary insured's coverage?

The Family Income Rider provides a monthly income benefit to the insured's family for a specified period following the primary insured's death. While it supports the family financially, it does not specifically add the spouse to the coverage, making it irrelevant to the question of adding a spouse to the policy.

The Decreasing Term Rider is a type of life insurance that provides coverage which decreases over time, usually aligned with a loan or mortgage. This rider does not pertain to adding a spouse to the primary insured's coverage; instead, it focuses on reducing the benefit amount over the policy's term.

The Cost of Living Rider adjusts the death benefit of the policy in accordance with inflation to maintain purchasing power. While it enhances the policy’s benefits over time, it does not facilitate the addition of a spouse to the coverage, thus failing to address the specifics of the question.