What type of server is most appropriate for storing a large list of names and phone numbers for a telephone company?

A directory server is specifically designed to store and manage large amounts of structured data, such as names, phone numbers, and other attributes linked to users. It provides a hierarchical structure that allows for efficient querying and retrieval of information, which is crucial when dealing with large datasets common in a telephone company's operations.

Directory servers often implement protocols such as LDAP (Lightweight Directory Access Protocol), which further enhances their capability to provide quick access to the information stored. This makes them particularly suitable for applications where data organization and fast lookup are important, such as in user authentication, contact lists, and similar tasks.

While other types of servers like database servers or file servers might handle similar data, directory servers are optimized for this exact purpose and can simplify management and scaling processes, making them the most appropriate choice for storing a list of names and contact information efficiently.