If a ball that a five-month-old infant is playing with rolls under a chair (and out of sight) ,the infant will not look for it.According to Piaget,why does this occur

A)  The infant does not understand the concept of roll. 
B)  The infant has not developed conservation. 
C)  The infant has not developed object permanence. 
D)  The infant has a short attention span.

Object Permanence

The understanding that objects continue to exist even when they cannot be observed (seen, heard, touched, smelled, or sensed in any way).

Conservation

The act of preserving, protecting, or restoring the natural environment and its wildlife.

Cognitive Development

The construction of thought processes, including remembering, problem solving, and decision-making, from childhood through adolescence to adulthood.