Which of the following schedules of reinforcement is the most robust and will be maintained for the longest period of time even when the reinforcer is removed?
A) Sheila is given money every other time she does her laundry.
B) Joseph is sometimes given money for completing his chores.
C) Paula is given a chocolate bar every Sunday if she completed her homework the previous week.
D) Alek is given a chocolate bar every time he does his homework on time.
