Which of these are the most common type of business letters?a.Letters of enquiryb.Letters of adjustmentc.Letters of orderd.Letters of application

All of the options you provided are common types of business letters. However, the frequency of each type can vary depending on the nature of the business.

a. Letters of Enquiry: These are written to ask for information from another company or individual. They are common in businesses that require information from suppliers or other external entities.

b. Letters of Adjustment: These are written in response to a complaint. They are common in customer service departments of businesses.

c. Letters of Order: These are written to place an order for goods or services. They are common in businesses that regularly order supplies from external suppliers.

d. Letters of Application: These are written to apply for a job. They are common for individuals seeking employment.

So, in general, all these types of letters are common in business communication. However, if we have to choose the most common type, it would probably be the Letters of Enquiry and Letters of Order, as these are integral parts of daily business operations.