下面语句段的输出结果是( ) int i = 9; switch (i) { default: System.out.println("default"); case 0: System.out.println("zero"); break; case 1: System.out.println("one"); case 2: System.out.println("two"); } A. default B. C. error default clause not defined D. no output displayed B. 编译错误 C. default zero D. 编译通过,但无输出