What is the difference between professional and casual communication styles? a. professional and casual communication styles are the same thing. b. a casual communication style is always acceptable no matter the circumstances. c. a professional style is used when writing papers for school and in correspondence between co-workers and with clients. a casual style is used when writing notes to friends, in texts, and in social media. d. a professional style is used when writing notes to friends, in texts, and in social media. a casual style is used when writing papers for school and in correspondence between co-workers and with clients.