The answer is A; manufacture. The word can be used as a verb when it means making something on a large scale. This is an action word, or a verb.
Ex: A company that manufactures paint.
When used as a verb, "manufacture" usually has an "s" or "ed" added on to the end of it (as seen above), except in certain cases (below).
Ex: To manufacture goods on such a large scale by hand must be so much work!
Hope this helps :)