Final answer:
To write a business letter in the SalesLetter program, follow a specific format including the date, addresses, salutation, body, and closing. Create a method called DisplayContactInfo() to include the contact information such as phone number, email address, and web address.
Step-by-step explanation:
To write a business letter in a program called SalesLetter, you can use the Main() method to display the letter using several WriteLine() calls. The letter should follow a specific format which includes the date, sender's address, recipient's address, salutation, body, and closing line. In order to display the contact information multiple times, you can create a method called DisplayContactInfo() that includes the necessary information such as phone number, email address, and web address.