Kris and Jen like to go fishing on the weekends. They drive the boat to their favorite spot, drop anchor, toss their lines in the water and wait. They never know how long it will be before they catch a fish,

but they spend the time listening to music, nibbling on snacks and wine, and sharing great conversation. The reward of catching a fish is uncertain, but they don't worry about it! This is an example of a __________ schedule of partial reinforcement.
a. variable ratio
b. fixed interval
c. variable interval
d. fixed ratio

Answer: C