The correct answer is scheme.
According to the psychologist, Jean Piaget, a scheme refers to thought patterns or cognitive structures that emerge during infancy, and aid the organization of knowledge. Schemes serve as building blocks of knowledge that help us form a mental model of the world around us. In this instance, by immediately trying put new toys in his mouth, and picking up and shaking the toys, Mark and Amanda's baby is trying to build a scheme- by forming mental representations of the new toys, shapes and colors around him.