Bill and joann have recently married and have made a commitment to each other that they will keep each other as the most important people in their lives, and stay together as long as they live. bill and joann’s joint commitment reflects the expectations of
a. self-disclosure.
b. permanence.
c. devotion.
d. convenience.

Permanence

Explanation:

Permanence is found in the sensory-motor stage. In this stage, a child understands that the object still exists if it removes from the sight of a child. This event occurs interdependently. Permanence means that permanent when an object is hidden from a child's insight, he still believes that the object still exists. This is the quality where mental representation is required in acquiring knowledge.  

So that here in the above context Bill and Joan who recently married committed their future that they never leave each other. They will keep each other in their life most important people.

the answer is:

c. economic output