U1S1E1R1N1A1M3E1
10 points
USERNAME is validvalid
an identifying sequence of characters used for logging on to a computer system [n USERNAMES]
an identifying sequence of characters used for logging onto a computer system [n -S]
an identifying sequence of characters used for logging on to a computer system [n USERNAMES]
an identifying sequence of characters used for logging onto a computer system [n -S]