Rhianna Rhianna Has Decided to Major in Psychology. She Is Very

Rhianna
Rhianna has decided to major in psychology. She is very interested in human behaviour and would like to have a career where she could help people. Rhianna takes the approach that people are very much influenced by their experiences. In fact, she's working with one of her professors on a research project in which they are looking at the effects of self-reward on study habits. Rhianna believes that she can take this knowledge and use it in other settings, like the workplace, in order to help people improve their productivity.
-Which unifying theme is reflected by Rhianna's use of research to investigate her ideas about human behaviour

A)  Psychology is theoretically diverse. 
B)  Psychology is empirical. 
C)  Behaviour is shaped by cultural heritage. 
D)  People's experience of the world is highly subjective.