A member of the human resources department received the following email message after sending an email containing benefit and tax information to a candidate: `Your message has been quarantined for the following policy violation: external potential_PII. Please contact the IT security administrator for further details`. Which of the following BEST describes why this message was received? 

Answer options:

A. The DLP system flagged the message.
B. The mail gateway prevented the message from being sent to personal email addresses.
C. The company firewall blocked the recipient`s IP address.
D. The file integrity check failed for the attached files.

A