Which one of the following commands can be used to change the value of a system variable?

(d) >>>>>>>>>>>>>>>>SETVAR

setvar - Assigns a new value to a system variable

The command is "Setvar" (d)

SET VAR can be used for changing the Value 

You can use a system variable to change a setting or to display the current status. Many system variable settings can also be modified in a dialog box or on the ribbon.

Setvar is the right option, because this command will give the new value to variable.

My answer is option (d) SETVAR

On Windows there is a shortcut for opening properties of System ie. Control Panel ->System It's WIN key on keyboard + Pause/Break (WIN+Break). This is extremely help fuland speeding up process of setting new environmental variables on Win8 because there you have to click through several windows in modern ui (Yeah. If it's modernthen I'll grow a cactus on my palm) which is just annoying. Of course you can create power shell script or use setvar command to control it.

D ) setvar can be used to change the value