Final answer:
An appointment request letter is formally used to set up a meeting. It outlines the meeting's purpose, proposes timings, and asks for confirmation.
Step-by-step explanation:
An appointment request letter is used to c. set up a meeting. This type of letter is a formal request for a meeting with someone or a group of people. It clearly outlines the reason for the meeting, suggests possible times for the meeting, and seeks confirmation of the meeting. Such letters are common in business settings when an individual or a company needs to discuss important matters, negotiate deals, or build professional relationships.