Answer: Functional play
Explanation:
Functional play is the playing process that involves playing with toys as per the purpose.It helps the infants to find the intention and sense of world. Playing in a manner to fulfill the purpose involves acts like pushing car toy on floor, rattling a rattler, dressing up dolls etc.It improves the congnitive skill of the children.
According to the question, Robin is involved in functional play in which he is performing the rattling function according to the intention of the rattler.He is interested to perform the same act as he correctly completing the toys objective that make him happy.