CR challengers

2.Dr. Bronstein, the noted oncological researcher, cites contradictory evidence in his article comparing smoking and environmental factors as cancer-causing agents in humans. He attributes the increase in cancer-related mortality “largely to lung cancer,” which he further notes, “is itself largely due to smoking.” In a similar vein, he makes reference to methodologically sound studies which pinpoint smoking as the actor which causes the greatest number of cancer deaths. Yet, he then goes on record as stating that he agrees with estimates that approximately 80 percent of human cancers are caused by environmental factors and not by smoking.
Which one of the following would most contribute to an explanation of the apparent discrepancy described above?

a.he sources which Dr. Bronstein cited for the statistics linking 80 percent of human cancers to environmental factors cited smoking as the next largest cause of human cancers.

b.r. Bronstein fails to make the assumption that a given cancer could not be attributable to more than a single cause.

c.Many of the cancers caused by environmental factors do not result in death.

d.It is possible for the results of even the most methodologically sound of studies to be proven wrong at a later date.

e. Dr. Bronstein fails to consider that many of the individuals whose cancers were environmentally caused may have also been smokers.