How far is it from Anna's home to school?
A:10 kilometers.
B:11 kilometers.
C:12 kilometers.
若直线l:ax+by+1=0(a>0,b>0)始终平分圆M:x2+y2+8x+2y+1=0的周长,则1a+4b的最小值为 ( )
根据句子意思,用括号中所给词的正确形式填空,每空填一词。