检索选修课程“C2”的学生中成绩最高的学生的学号。正确的SELECT的语句是 ______。

A．SELECT S# FROM SCWHERE C#="C2" AND GRADE＞ =(SELECT GRADE FROM SCWHERE C#="C2")

B．SELECT S# FROM SCWHERE C#="C2" AND GRADE IN(SELECT GRADE FROM SCWHERE C#="C2")

C．SELECT S# FROM SCWHERE C#="C2" AND GRADE NOT IN(SELECT GRADE FROM SCWHERE C#="C2")

D．SELECT S# FROM SCWHERE C#="C2" AND GRADE＞ =ALL(SELECT GRADE FROM SCWHERE C#="C2")

癌性空洞与结核性空洞鉴别的关键点在于前者（）

A.空洞较大

B.空洞周围可见纤维条索

C.空洞内有液平

D.空洞边界不清楚

E.洞壁凹凸不平，可见壁结节