11. object permanence can be developed by placing objects a. on top of another object. b. in the baby's hand. c. on top of a table. d. under a blanket.

D. under a blanket

Explanation: Object permanence can be developed by placing objects under a blanket. Object permanence is the notion that objects continue to exist even though they cannot be perceived through the senses. The first psychologist who studied this notion was the Swiss Jean Piaget in his studies of the infant's cognitive development. During the first stages of the infant's cognitive development, the existence of objects depends on perception.

the answer would be c   i believe thats the most reasonable answer