The correct answer is B. Letter
Explanation:
The written communication used in job contexts or between different companies is usually referred as business writing that allows people involved in a company or business to communicate effectively, for doing this, there are types of writing depending on the purpose and communicative situation. In the case of internal communication and external communication, letters are the most common business writing used as this allows the communication between different companies or departments to report some situation, ask something or send any other type of formal message. Considering this, the best type of business writing to report a billing error to the same company or other company are letters as there are formal documents that allow the communication between departments or different companies and are very useful and appropriate to report any situation including an error.
