Total color blindness ______ is the result of a defect in the retina.A．a rare condition
已帮助 人
Total color blindness, ______, is the result of a defect in the retina.
A．a rare condition that
B．a rare condition
C．that a rare condition
D．is a rare condition
请帮忙给出正确答案和分析，谢谢！