Your Web site processes book orders. One of the application methods contains the following code segment.Dim doc As New XmlDocument()doc.LoadXml("<book><discount>10</discount>" &_"<title>Dictionary</title></book>")You need to remove the discount element from XmlDocument. Which two code segments can you use to achieve this goal? ()
A、A. Dim root As XmlNode = doc.DocumentElementroot.RemoveChild(root.FirstChild)
B、B. Dim root As XmlNode = doc.DocumentElementroot.RemoveChild(root.SelectSingleNode("discount"))
C、C. doc.RemoveChild(doc.FirstChild)
D、D. doc.DocumentElement.RemoveChild(doc.FirstChild)