Securing Email with Cisco Email Security Appliance (SESA) — Question 132

The CEO sent an email indicating that all emails containing a string of 123ABCDEFGHJ cannot be delivered and must be sent into quarantine for further inspection. Given the requirement, which regular expression should be used to match on that criteria?

Answer options

• A. \d{3}[A–Z]{9}
• B. {3}\d{9}[A–Z]
• C. \w{3}[A–Z]{9}
• D. \\D{3}[A–Z]{9}

Correct answer: A

Explanation

The correct answer, A, uses the regular expression \d{3}[A–Z]{9}, which accurately matches three digits followed by nine uppercase letters. Option B incorrectly places the quantifier before the digit, while option C uses \w instead of \d, which includes letters and underscores, and option D incorrectly uses \D, which matches non-digit characters.