各位大大安安，今天寫到一題關於登入介面如何設計比較安全的題目：
The following are three possible logon scenarios. Explain why option (c)
below is preferable in term of system security.
a.
Welcome to XYZ computing
Enter username: jones
Invalid username
Enter username:
b.
Welcome to XYZ computing
Enter username: smith
Enter password: password
Invalid access
Enter username:
c.
Enter username: smith
Enter password: password
Invalid access
Enter username: smith
Enter password: FpQr56
Welcome to XYZ computing
a的問題比較明顯，我已經知道了。
我不太懂的是b和c的差別，
那句"Welcome to XYZ computing"的出現時機會對安全有什麼影響呢？
感謝各位大大！