Which of these processes was used to form the word typewriter? Use a dictionary if necessary.

a-prefix addition
b-suffix addition
c-compounding
d-telescoping
e-shortening
f-back formation

f-back formation

Explanation:

The process of back formation was used in forming the word typewriter.

Back formation is one of the process of creating a new lexeme  or word. It entails the creation of new word by the removal of a part of another word. Simply put, it is a shortened word created from a longer one. Usually, the word formed is the based of another word. Typewriter is formed from the word typewriting.

They are different because conan doyle shows he conflict between the to storys

Am i to late to answer your question