Explanation:

• Retina scan: Scans the unique pattern of a person's retina.
• Commonly used for security and identification.
• Handwriting/Signature:Analyzes the style and pressure of writing.
• Used for verifying identities in documents and transactions.
• Heart rate: Typically not used as a standalone biometric method.
• More often used in conjunction with other methods, like fingerprint or facial recognition, for multi-level security.
• Correct Answer: Option 3: 1 and 2 only