选C.
在牛津英英字典里,admit词条下明确标出它有“allow to enter/join(准许进入某处)”的意思,admit sb.to+ 名词sth.(地点/组织/节目）.并列有相似的例句：
Each ticket admits one adult and one child.(每张票可供一个成人和一个小孩入内.)
You will not be admitted to the theatre after the performance has started.（演出开始后不准进入剧场.）