Answer:
Darren is using C. shaping to get his son to eat his peas.
Explanation:
Shaping is a tactic used within Operant Conditioning, which is understood as the process for a subject to acquire a certain behavior through reinforcements.
Shaping occurs when the reinforcements occur during a successive pattern of the behavior, not only whenever a behavior is present.
We can see it clearly in this example; Darren slowly starts to praise (reinforce) his son's behaviors, gradually moving from moving his fork towards the peas until he moves the fork with the pea to its mouth.