Answer: Secondary circular reaction
Explanation:
Secondary circular reaction is which infants tend to repeat the actions or activities intentionally that they found pleasurable in form of response .These activities are performed through their body parts like, hands, legs etc as well as objects like toys etc.This phase usually occurs when babies range from 4 months old-8 months old.
According to the question, Antonio is displaying secondary circular reaction by repeating the act of hitting his arm to move mobile so that it can swing again.