In the Context of Human Development,who Among the Following Is

In the context of human development,who among the following is most likely studying physical processes?

A) Sylvia,who is analyzing hormonal changes in teenage girls
B) Robert,who is studying the ability of boys to memorize difficult scientific equations
C) Divya,who is analyzing the capacity of teenage boys to care for senior citizens
D) Reuben,who is studying emotional changes in young women