Which of the following is the MOST effective method to counter phishing attacks?

Phishing attacks exploit human vulnerabilities, making user awareness and training the most effective countermeasure. Training ensures users recognize and avoid phishing attempts, significantly reducing the likelihood of successful attacks. While antispam solutions (D) and intrusion detection systems (B) help mitigate technical aspects, they are not as impactful as educating users. An acceptable use guide (C) provides rules but does not directly address phishing-specific tactics.