George, a Child, Sees a Hammer in His Father's Toolbox

George, a child, sees a hammer in his father's toolbox, but he only has a vague idea about how to use it. He also sees some nails in the toolbox and learns that they can be driven into walls. George later realizes that the hammer is hard and heavy and can be used to drive the nails into walls. In the context of Jean Piaget's theory of infant development, the grouping of knowledge or thoughts by George into a higher-order system is known as

A) assimilation.
B) accommodation.
C) equilibration.
D) organization.