What is incorrect about the inside address listed in a business letter?

In a business letter, the inside address typically includes essential information such as the recipient's name, title, and address details, allowing for clear identification and correspondence. The assertion that using both "Dr." and "D.D.S." is redundant can be considered incorrect because it is common practice to use a title like "Dr." to denote a doctor's professional designation, while "D.D.S." (Doctor of Dental Surgery) specifically identifies the degree earned. Including both adds clarity and formality to the communication, especially in a professional setting such as a dental practice, where establishing credentials can be important for building rapport and trust.

The other aspects, such as the state abbreviation, street address, and inclusion of the patient’s name, are all elements that could lead to common errors in addressing letters, but they do not pertain to the redundancy of titles, which maintains significance in professional communication.