C#

// Method used to Serialize C# Objects into XML
        private string serializeXML(object objToSerialize)
        {
            String XmlizedString = null;
            MemoryStream mStream = new MemoryStream();
            XmlSerializer xs = new XmlSerializer(objToSerialize.GetType());

            XmlTextWriter xmlTextWriter = new XmlTextWriter(mStream, Encoding.UTF8);
            xs.Serialize(xmlTextWriter, objToSerialize);
            mStream = (MemoryStream)xmlTextWriter.BaseStream;
            XmlizedString = U8ByteArrayToString(mStream.ToArray());
           

 // Method used to Convert UTF8 ByteArray into a String
        private String U8ByteArrayToString(Byte[] characters)
        {

            UTF8Encoding encoding = new UTF8Encoding();
            String conString = encoding.GetString(characters);
            return (conString);
        }

using System;
using System.Linq;
using System.Xml.Linq;

class Program
{
    static void Main()
    {
        XDocument document = XDocument.Load(@"d:\test.xml");

        var priceInfo = from e in document.Descendants("MPrice").Elements("Price")
                        let start = DateTime.Parse(e.Descendants("StartDt").FirstOrDefault().Value)
                        let end = DateTime.Parse(e.Descendants("EndDt").FirstOrDefault().Value)
                        where start < DateTime.Now && end > DateTime.Now
                        select new { Id = e.Parent.Element("Id").Value, ListPrice = e.Element("ListPrice").Value };

        Console.WriteLine(priceInfo.FirstOrDefault().Id);
        Console.WriteLine(priceInfo.FirstOrDefault().ListPrice);
    }
}

The following is the metatag:
<ns2:RetsubPack serviceSuccessful="true" returnCode="0" xmlns:ns2="http://test1/test">
    <statusDescription>Package Details retrieved Successfully</statusDescription>
    <PackageDetails>
        <Type>type2</Type>
        <Category>dog</Category>
        <ContName>Co 1</ContgName>
        <TotalTrans>0</TotalTrans>
     </PackageDetails>
    <NumberOfDocuments>3</NumberOfDocuments>
    <subDocuments attachmentId="xx1">
        <DocumentMetadata>
            <DocumentTypeCode>Spreadsheet1</DocumentTypeCode>
            <PackageId>pkg1</PackageId>
        </DocumentMetadata>
    </subDocuments>
    <subDocuments attachmentId="xx2">
        <DocumentMetadata>
            <DocumentTypeCode>Spreadsheet2</DocumentTypeCode>
            <PackageId>pkg1</PackageId>
        </DocumentMetadata>
    </subDocuments>
    <subDocuments attachmentId="xx3">
       
</ns2:RetsubPack>