31 The boundaries between the sane and the mentally ill have become the battleline that divides two opposingschools of thought.
(A) The limitations of healthy and mentally ill people result in two types of thoughts.
(B) The outlines of sane and insane people resemble those of the two schools of thoughts.
(C) The definition of the sane in contrast to mentally ill people has become the center of debate between two schools of thought.
(D) The boundaries between sane and mentally ill people have become the main topic to which the two schools of thought are opposed.