把一个周长是18.84分米的圆平均分成两个半圆，每个半圆的周长是[ ]

A．15.42分米

B．9.42分米

C．12.24分米

设有以下函数过程：Function fun(m As Integer) As Integer Dim k As Integer, sum As Integer sum = 0 For k = m To 1 Step -2sum = sum + k Next kfun = sumEnd Function若在程序中用语句s=fun(10)调用此函数，则s的值为 _________。