Which of the Following Best Defines Health Psychology

Which of the following best defines health psychology?

A) Using psychological theories and principles to tackle problems in the areas of mental health, education, product design, ergonomics, and law
B) Understanding the psychological influences on how people stay healthy, why they become ill, and how they respond when they get ill
C) Applying the principles of biology in order to study the anatomy of a human being
D) Diagnosing, preventing, and treating a disease without including the option of surgery