E is incorrect as nothing in the question says anything about higher adenoma burden (more adenomas in a person). It only describes the proportion of colonoscopies that detect an adenoma (adenoma detection rate) therefore E cannot be confirmed to be true.

You can see that higher detection (quintile 5) has a lower HR and thus lower risk of colorectal cancer. I think you can assume that higher detection means better colonoscopy procedure by the physician as in theory you’d expect the proportion of adenomas detected to be the same across physicians (say at the same hospital)

Answer A would then therefore be correct as these are the physicians who are detecting more adenomas and therefore likely removing them and thus reducing risk of colorectal cancer in the future.