A、<span style="FONT-FAMILY: 宋体">造价最低</span>
B、<font face="宋体">糙率最小<span lang="EN-US"> <p></p></span></font>
C、<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: ">在<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/35292f2f-2fd3-494d-bf03-ed57bf26cf7a.gif"title="ex_1257560059633_0.gif" alt="ex_1257560059633_0.gif"/>一定时，过流面积<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/94e4b12a-546a-44ad-aee3-7cd2502f5e7b.gif"title="ex_1257560081543_0.gif" alt="ex_1257560081543_0.gif"/>最大</span>
D、<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-size: 12.0pt; mso-bidi-font-family: "><IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/435d27a6-32ec-4902-9ed7-6189797795ab.gif"title="ex_1257560106560_0.gif" alt="ex_1257560106560_0.gif"/>在一定时，过流面积<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/e2cba6b5-a166-4464-b722-59650ae29f66.gif"title="ex_1257560130138_0.gif" alt="ex_1257560130138_0.gif"/>最大</span>