对于潮汐河流或流向不定的桥位，桥墩设计时应选择的截面形式为：  。

A、<span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-family: " times="" new="" roman";="" mso-font-kerning:="" 1.0pt;="" mso-ansi-language:="" en-us;="" mso-fareast-language:="" zh-cn;="" mso-bidi-language:="" ar-sa"="">矩形</span>

B、<span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-family: " times="" new="" roman";="" mso-font-kerning:="" 1.0pt;="" mso-ansi-language:="" en-us;="" mso-fareast-language:="" zh-cn;="" mso-bidi-language:="" ar-sa"="">圆端形</span>

C、<span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-family: " times="" new="" roman";="" mso-font-kerning:="" 1.0pt;="" mso-ansi-language:="" en-us;="" mso-fareast-language:="" zh-cn;="" mso-bidi-language:="" ar-sa"="">圆形</span>

D、<span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-family: " times="" new="" roman";="" mso-font-kerning:="" 1.0pt;="" mso-ansi-language:="" en-us;="" mso-fareast-language:="" zh-cn;="" mso-bidi-language:="" ar-sa"="">尖端形</span>