问题：

[单选]

You are employed as the enterprise exchange administrator at TestKing.com. TestKing.com makes use ofMicrosoft Exchange Server messaging solution. You are responsible for managing the Exchange Server2010 organization.
A TestKing.com policy dictates that e-mail messages older than six months be automatically deleted. Youreceive an instruction form the CIO to recommend a solution that will stop the e-mail of users on a longsabbatical leave to be deleted. You should ensure that the users are able to view the e-mail messageswhen they resume work.
What should you do？（）

A . This can be accomplished by recommending a Transport Protection Rule.
B . This can be accomplished by recommending a legal hold.
C . This can be accomplished by recommending an Outlook Protection Rule.
D . This can be accomplished by recommending a retention hold.