All options except C contribute to optimizing the rule for credential stuffing. A: Integrate with IdP logs: This is crucial. If MFA fails or is bypassed, it significantly elevates the risk associated with multiple failed logins, distinguishing it from simple password resets or mistyped credentials. B: Leverage geographic anomaly detection: XSIAM can baseline user behavior. Detecting logins from 'unusual' geographies (based on historical patterns) is a strong indicator of compromise or suspicious activity, distinguishing legitimate travel from an attacker. D: Dynamic allowlist for VPNs with user-agent correlation: This precisely addresses the VPN false positive scenario. By combining IP range allowlisting with a device/user-agent check, legitimate VPN usage can be excluded while still catching attackers trying to use VPNs. E: Session-based correlation for distinct IPs: Credential stuffing often involves attackers trying many credentials from many IPs against a few target accounts. Focusing on the 'number of distinct IPs per user' within a time window, rather than just raw failed attempts, is a very effective way to detect these automated attacks. C: Increase threshold to 1000: While it would reduce false positives, it's too aggressive and would likely lead to missing many real attacks that use lower, more distributed attempt volumes.