Which of the following is an example of the criterion of "Strength of Association" from Hill's criteria for causation?
A) In a study of the association between abx exposure and development of C. difficile infection, the odds ratio was 2:3
B) In a study of the association between abx exposure and development of C. difficile infection, the author's conclusions are consistent with those of three other studies
C) In a study of the association between abx exposure and development of C. difficile infection, antibiotic therapy began an average of 3 weeks before C. difficile infection
D) In a study of the association between abx exposure and development of C. difficile infection, prolonged antibiotic therapy was a greater risk factor for C. difficile infection