Step 1: Define a cookie.
A cookie is a small text file that a website asks the browser to store on the user's computer.
Step 2: Note what cookies remember.
They hold things like login state, language choice, cart contents and site preferences so the site can recognise you on a return visit.
Step 3: Reject option A.
Cookies are plain text files, not viruses, and do not by themselves steal data.
Step 4: Reject option B.
The list of visited sites is the browser history, a separate feature from cookies.
Step 5: Reject option D.
Deleting cookies clears saved preferences and sessions but does not wipe history or email drafts, so this claim is false.
Step 6: Pick the correct description.
The accurate description is a small text file stored on the user's computer to save site preferences.
\[ \boxed{\text{Small text file store on the user's computer to save site preferences.}} \]