Answer:
A. Trademark
Step-by-step explanation:
Trademark represents a phrase, a symbol, a picture or anything like that for a specific product, which if registered, states the uniqueness of the product from similar products.
Here, in the given case Hillward Bakers did not register the trademark, which is now used by Hobert Bakers.
Accordingly Hillward Bakers cannot proceed in any legal action as against the logo used by Hobert Bakers, which was designed and used by Hillward Bakers.