A controversial program rewards prison inmates who behave particularly

A controversial program rewards prison inmates who behave particularly well in prison by giving them the chance to receive free cosmetic plastic surgery performed by medical students. The program is obviously morally questionable, both in its assumptions about what inmates might want and in its use of the prison population to train future surgeons. Putting these moral issues aside, however, the surgery clearly has a powerful rehabilitative effect, as is shown by the fact that, among recipients of the surgery, the proportion who are convicted of new crimes committed after release is only half that for the prison population as a whole.

A flaw in the reasoning of the passage is that it
A. allows moral issues to be a consideration in presenting evidence about matters of fact
B. dismisses moral considerations on the grounds that only matters of fact are relevant
C. labels the program as "controversial" instead of discussing the issues that give rise to controversy
D. asserts that the rehabilitation of criminals is not a moral issue
E. relies on evidence drawn from a sample that there is reason to believe is unrepresentative

I am not 100% sure about the ans so please discuss. My ans is E