You work as an application developer at Certkiller .com. Certkiller .com has been contracted to develop an application for the local bank.You have been given the responsibility of creating this application and need to store each transaction record， which is identified using a complex transaction identifier，in memory. The bank informs you that the total amount of transaction records could reach 200 per day. To achieve this， you decide to utilize one of the existing collection classes in the .NET 2.0 class library. You need to ensure that you the collection class you select is the most efficient one for storing transaction records.What should you do？（）