Final answer:
To buy fish for ichthyomancy, you must go to the shop called Slug & Jiggers Apothecary. (Option c)
Step-by-step explanation:
To practice ichthyomancy, a form of divination involving the observation of fish behavior, one would likely visit Slug & Jiggers Apothecary. Among the given options, Slug & Jiggers Apothecary is the most relevant for obtaining magical ingredients, including enchanted or specially bred fish used in divination practices within the wizarding world. This apothecary, featured in the Harry Potter series, caters to the needs of witches and wizards seeking magical creatures, potions ingredients, and divination tools.
Ollivanders is renowned for selling wands, Flourish and Blotts for books, and Wiseacre's Wizarding Equipment for general magical supplies, none of which are specifically associated with ichthyomancy. Slug & Jiggers Apothecary, with its focus on magical ingredients, aligns with the requirements for obtaining fish used in divination practices, making it the most suitable option for individuals interested in the art of ichthyomancy within the magical realm.
Therefore, the correct option is: c) Slug & Jiggers Apothecary