以下程序段运行的结果是______。Dim a(-1 To 5)As BooleanDim flag As Booleanflag=FalseDim i As IntegerDim j As IntegerDo Until flag=True For i= -1 To 5j=j+1If a (i)= False Then a(i)=TrueExit ForEnd IfIf i=5 Then flag=True End If Next Loop Print j

A．20

B．7

C．35

D．8

明步木楼梯的踏步板和踢脚板，分别嵌在斜梁的凹槽内。( )