Which of the following hypothetical scientific discoveries, if made, would weaken the author's arguments concerning the ethical risks of human cloning

A． Through careful and documented study, cloning proves to be less risky than consanguineous breeding.
B． A laboratory process for reducing the number of stages in the cell division process is developed.
C． A non-cloning method for curing human fertility is discovered, thereby reducing the need to rely upon cloning.
D． A procedure for easing the acclimation of a foreign nucleus in the embryonic host is established.
E． A means of assessing genetic mistakes in a foreign nucleus before its implementation into a clone is devised.