The correct option is 1, 2, and 3, as all three methods—iris scanning, retinal scanning, and voice recognition—are established biometric identification techniques that utilize unique physiological and behavioral characteristics of individuals. Biometric systems enhance security by leveraging these distinct traits, which are difficult to replicate or alter, making them effective for identity verification and personal authentication in various applications, including law enforcement and secure access control. This aligns with UPSC's emphasis on understanding advancements in technology and their implications for society, governance, and security.