Answer:
OC. between two private individuals.
Step-by-step explanation:
A business letter is a formal document written to convey an official or commercial message. It is written in a standard format. A Business letter is usually short, clear, and concise.
Two private individuals will probably communicate using personal letters. Unlike a business letter, a personal letter uses a friendly and relaxed tone. They are no laid down formats to consider. Personal letters may convey messages concerning the writer or recipient's social, religious, or economic matters.