Research Examining Piaget's Theory in a Number of Different Cultures

Research examining Piaget's theory in a number of different cultures indicates that

A) children seem to pass through Piaget's stages in the same order and at the same ages world-wide.
B) children seem to pass through Piaget's stages in the same order but not necessarily at the same ages world-wide.
C) all children regardless of cultural background or educational level eventually attain formal operations.
D) the rates at which individuals achieve formal operations are the same in industrialized and non industrialized countries.