单项选择题

A.=IF(A1>=85,"优良", IF(A1>=60, "及格", IF(A1<60, "不及格")))
B.=IF(A1>=85, "优良", 85>A1>=60, "及格", A1<60, "不及格")
C.=IF(A1>=85, "优良"), IF(A1>=60, "及格"), IF(A1<60, "不及格")
D.=IF(A1>=85, "优良",IF(A1>=60, "及格", "不及格"))