What research method did Kohlberg use to develop his theory of moral development?

A) field experiments on children
B) longitudinal studies of families
C) interviews with children
D) case studies of children

Kohlberg used interviews with children as his primary research method to develop his theory of moral development. He presented children with hypothetical moral dilemmas and asked them questions about their reasoning behind their moral judgments. This allowed him to study the development of moral reasoning over time in individuals.