DrOswald Conducts a Study Examining the Relationship Between the Number

Dr.Oswald conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction.She randomly samples 1,500 elderly men and women in the Memphis,Tennessee,area in the southern United States.Below are her findings.
-Life satisfaction and experience of daily stress: r = -.57 ( p = .01)
-Number of friends one has and experience of daily stress: r = .09,not sig.
-Number of friends one has and life satisfaction: r = .36 ( p = .04)

-In evaluating Dr.Oswald's study,you question the construct validity of the study.Which of the following questions would you be asking?

A) How did Dr.Oswald recruit her participants?
B) Which statistic did Dr.Oswald compute?
C) How reliable is the measure of daily stress?
D) Does the number of friends cause people to experience less stress?