You have a computer that runs Windows XP Professional. Two users named User1 and User2 share the computer. User1 and User2 encrypt files on the computer. User1 encrypts a file named file1. doc. You need ensure that both User1 and User2 can view the contents of file1. doc. What should you instruct User1 to do?（） 

• A、Add the certificate of User2 to file1. doc. 
• B、Assign User2 the Full Control NTFS permission on file1. doc. 
• C、Copy file1. doc the %systemroot%/documents and settings/all users/ folder.
• D、Move file1. doc to the %systemroot%/documents and settings/all users/ folder.