执行下列程序后，在文本框中输入字符“d”，输出结果为______。
Private Sub Form_Load()
Text1=""
End Sub
Private Sub Text1_Change()
Print Text1.Text
End Sub
Private Sub Text1_KeyDown(KeyCode As Integer, Shift As Integer)
Print Chr(KeyCode)
End Sub
Private Sub Text1_KeyPress(KeyAscii As Integer)
Print Chr(KeyAscii)
End Sub

A．D
d
D

B．d
d
D

C．d
D
d

D．D
d
d

解释名词；滚动轴承的寿命；滚动轴承的基本额定动载荷。