How would you check a specific field of xml in c#?

Question

I have an application that is using XML to send and receive information. I will receive XML data like the following:

<?xml version="1.0" encoding="ASCII" ?> 
<Response> 
<ID>1234567</ID> 
<Transaction>Connect</Transaction> 
<Data>data</Data> 
</Response>

Based on the value in the 'Transaction' I field, I plan to use XmlSerializer.Deserialize to deserialize the data packets to the appropriate class type. The example above would be the 'Connect' class that I would have to deserialize to:

using System.Xml.Serialization;

namespace XMLResponse
{
    [XmlRoot("Response")]
    public class Connect
    {
        public Connect()
        {

        }

        public long ID { get; set; }
        public string Transaction { get; set; }
        public string Data { get; set; }
    }
}

I am receiving the data as a byte array right now, I am putting it in a MemoryStream for use with XmlSerializer.Deserialize, but I can put it in a string if needed. What is the best way to pull out that field so I can Deserialize with the right class?