Which One of the Following Statements Best Describes Vygotsky's Concept

Which one of the following statements best describes Vygotsky's concept of internalization?

A) As children grow older, they develop an increasing ability to think about events in abstract rather than concrete terms.
B) With age, children become more sophisticated at solving problems, largely because their parents and teachers give them increasingly challenging problems to solve.
C) Over time, children acquire more self-confidence about their ability to deal with the world.
D) Through their social interactions with other people, children develop new ways of mentally approaching and thinking about a task.