运行下列程序，单击窗体后输出的结果是( )。

Private Sub Form_Click()

D．im a

D．im s As Integer, i As Integer

a = Array(1, 2, 3, 4, 5, 6)

s = 1

F．or i = 5 To 1 Step -2

s = s * a(i)

Next i

Print s

E．nd Sub

A． 15

B． 48

C． 120

D． 720