题目内容：
What is the most important one among the realities listed?[A] New vulnerabilities will be introduced into your environment every day.
[B] If employees disregard warnings about the hazards of opening questionable email attachments, the manager should educate them about properly configuring firewalls and intrusion detection systems for their PCs.
[C] Managers have more responsibility than ever.
[D] Security managers are asked to support increasing degrees of network availability and access.
参考答案：