An infant puts her thumb in her mouth repeatedly because she finds it enjoyable or interesting. piaget would describe this as a:

Piaget will describe an infant who is sucking the thumb as the infant is exploring the world and experiencing it for the first time with trial and error, due to which it learns the texture consistency and mature of objects around, and if the infant finds it enjoyable or interesting then it will do it again and again just as the sucking reflex in new borns.

The answer - c apex