Choose the correct arrangement of the sentences to make a meaningful paragraph/letter.

a. For many years, doctors, veterinarians, pharmacists, engineers, and lawyers have used it to continue their professional education.
b. Recently, academic instructions have been using distant education to reach a more diverse and geographically dispersed audience not accessible through traditional classroom instructions.
c. Distant education is a rapidly developing approach to instructions throughout the business.
d. The approach has been widely used by business, industrial, and medical organizations.