Which tool should you do?

Your network contains a server named Server1 that has the Remote Desktop Session Host (RD Session Host) role service installed.
A user named User1 connects to Server1 and starts an application named App1.exe.
User1 reports that App1.exe is unresponsive and cannot be closed.
You need to terminate App1.exe for User1 only.
Which tool should you do?

A.
Qprocess

B.
Quser

C.
Rwinsta

D.
Tskill

Explanation:
Tskill
Ends a process.
Syntax
tskill {ProcessID | ProcessName} [/server:ServerName] [{/id:SessionID | /a}] [/v]
Parameters
ProcessID : The ID of the process you want to end.
ProcessName : The name of the process you want to end. You can use wildcards to specify this parameter.
/server: ServerName : Specifies the terminal server containing the process you want to end. Otherwise, the current terminal server is used.
/id: SessionID : Ends the process running in the specified session.
/a : Ends the process running in all sessions.
/v : Displays information about the actions being performed.
/? : Displays help at the command prompt.
tskill App1.exe /server:Server1 /id:
Source: http://technet.microsoft.com/en-us/library/bb490806.aspx