Name a common protocol used to retrieve emails from a server.

IMAP, or Internet Message Access Protocol, is a widely used protocol for retrieving emails from a mail server. Unlike other protocols that may download emails and remove them from the server, IMAP allows users to access and manage their emails directly on the server. This means that emails remain stored on the server and users can organize, sort, and delete messages without permanently removing them from the server.

A significant advantage of IMAP is that it supports multiple device access, allowing users to view and manage their email across various devices like computers, smartphones, and tablets while maintaining a synchronized inbox. This is particularly useful for users who check their email from multiple locations.

In contrast, other protocols like FTP are designed for transferring files rather than emails. SMTP is focused on sending emails from a client to a server or between servers, not retrieving them. HTTP, while essential for web communication, is not used for email retrieval. Thus, IMAP stands out as the correct choice for accessing and managing emails stored on an email server.