Final answer:
Anne of Cleves is the woman who was divorced by King Henry VIII because he was disappointed with her appearance, not due to failure to produce an heir or accusations of adultery.
Step-by-step explanation:
The woman who was divorced by the King because he found her unattractive, and whose story involves a horse's head, is c) Anne of Cleves.
King Henry VIII sought an annulment from Anne of Cleves, not because she bore him no children or was accused of adultery, but rather because he was reportedly disappointed with her appearance upon meeting her in person.
There's a tale that Henry referred to her as the 'Flanders Mare', likening her to a horse, although the authenticity of this insult is debated among historians.