Ross, Lepper, and Lord Showed Mixed Research Results on the Deterrence

Ross, Lepper, and Lord showed mixed research results on the deterrence effect of the death penalty to students who either favoured or opposed the death penalty. Showing the two sides this identical body of mixed evidence

A) had no effect on their pre-existing opinions.
B) narrowed the disagreement between the two sides.
C) changed the views of the pro students but not the anti.
D) increased the amount of disagreement between them.