One reason you might want to write a letter is to register a complaint.
One reason you might want to write a letter is to register a complaint. To arrive at this answer, it is necessary to consider the options provided and determine which one is most appropriate. The other options, such as arguing with a colleague, making a purchase, or asking about borrowing money, are more commonly done through other means of communication like face-to-face conversations, emails, or phone calls. However, registering a complaint often requires a well-documented and formalized approach, which can be effectively achieved through writing a letter or an email. This allows you to clearly articulate your concerns and provide supporting evidence, ensuring that your complaint is properly addressed and resolved.