单项选择题
A.lgKNY-lgKMY≥2且lgcK'MY和lgcK'NY均大于6 B.lgKNY-lgKMY≥5且lgcK'MY和lgcK'NY均大于3 C.lgKMY-lgKNY≥5且lgcK'MY和lgcK'NY均大于6 D.lgKMY-lgKNY≥8且lgcK'MY和lgcK'NY均大于4