The correct answer is A. when sending an invitation; when sending an invitation, it would be a personal letter because personal information can be embedded in the letter.
The other options B, C, D are formal letter. You wouldn't send anything personal when providing information about services OR when answering ad for a job OR when asking a company for information.
The correct answer is A. when sending an invitation; when sending an invitation, it would be a personal letter because personal information can be embedded in the letter.
The other options B, C, D are formal letter. You wouldn't send anything personal when providing information about services OR when answering ad for a job OR when asking a company for information.
