Final answer:
Lev Vygotsky is the cognitive developmental theorist who emphasized the role of schooling and social-cultural context in cognitive development.
Step-by-step explanation:
The cognitive developmental theorist who emphasized the importance of schooling on cognitive development is b) Lev Vygotsky. His sociocultural theory of development states that human development is deeply rooted in one's culture. Vygotsky highlighted the role of social interactions and language, explaining that a child's cognitive growth is interconnected with their cultural and historical context. Unlike Jean Piaget, who focused on cognitive growth through individual stages, or Lawrence Kohlberg, who specialized in moral development, Vygotsky believed that cognitive development is fundamentally linked to the social and educational environment surrounding the individual.