Anthony a authoring a book.___ he also acts as its editor and publisher a. however
b. also
c. in contrast

a. however

Explanation:

Anthony is authoring a book. "However", he also acts as its editor and publisher.

"However" is the correct word that fits into this sentence and that gives it a whole lot of meaning. The word in the sentence simply means that though Anthony is the one writing the book yet he is still the one editing and publishing it.