__________is the primary cause of cognitive development, according to Lev Vygotsky.

Correct option is C

Lev Vygotsky emphasized social interaction as the primary cause of cognitive development. He believed that learning is fundamentally a social process, where interactions with more knowledgeable others (adults or peers) play a crucial role in the development of higher cognitive functions. Vygotsky's theory highlights the importance of cultural and social context in cognitive growth.