—_____________have you been away from your hometown,Janet?              

—since 5 years ago.         [ ]

A. How many

B. How long

C. How much

D. How often

以下程序的输出结果是【 】。#includemain( ) {char a[]={′＼1′,′＼2′,′＼3′,′＼4′,′＼O′}；printf("％d％d＼n",sizeof(a),strlen(a))； }