Answer: Option A, type A personality increases a person's level of stress, which in turn increases vulnerability to CHD.
Explanation: Friedman and Rosenman described three different types of personalities: Type A, type B and type C. The first one (type A) describes the group of people which personality is explosive, competitives, always in need to success; because of the particularities of this group, level of stress are higher in order to excell in all contexts and of course, if they don't they will feel frustrated, which leads them in a constant patter of stress. High levels of stress accelerate cardiac pressure, and that could turn into a coronary heart desease; compared with the other two types of personality, type A holds the higher level of stress.