Which of the following BEST mitigates ransomware threats?

Immutable data storage is highly effective against ransomware threats because it ensures that stored data cannot be altered or deleted, even by malicious actors. This allows organizations to recover from ransomware attacks quickly without paying ransoms. Phishing exercises (A) and endpoint anti-malware (D) are preventive measures, while blocking wireless networks (C) is unrelated to ransomware mitigation.