Which piece of information is required for authentication by an authorized representative?

The required piece of information for authentication by an authorized representative is typically a zip code or phone number because these details are often used to verify the identity of a customer while maintaining privacy and security. These identifiers are commonly associated with customer accounts and can confirm that the person attempting to access information is indeed authorized. They strike a balance between accessibility and security, ensuring that sensitive information is protected without making the authentication process overly burdensome.

In contrast, full name and address, while useful, might not be unique enough to establish identity on their own, as they may not differentiate between individuals. Meanwhile, the use of the social security number is generally avoided in many contexts to protect against identity theft and privacy concerns, making it less suitable for authentication procedures in a customer service setting.