Answer:
Rebecca and Bob are demonstrating the cooperation that is evidence of parental alliance.
Step-by-step explanation:
An alliance is an association in which both parts are mutually benefited.
A parental alliance is the same concept in which both parents respect and value each other, being mutually benefited by their decisions and division of tasks.
In this case, Rebecca and Bob agree that they are both responsible for their baby so the other one can have a break. They share responsibility with the drop-off and pick up and they respect each other's decisions.
They have formed a healthy parental alliance.