Final answer:
Ursula mentioned that Ariel signed a contract to become a human, which entailed giving up her voice in order to gain legs with the condition that she must receive a true love's kiss within three days or revert to a mermaid.
Step-by-step explanation:
The contract Ursula mentioned that Ariel signed was A) A contract to become a human. In Disney's The Little Mermaid, Ariel, the main character, signs a contract with the sea witch Ursula. The terms of the contract specifically stipulate that Ariel will become a human for three days. However, a critical part of this agreement is that Ariel must give up her voice to Ursula in exchange for legs. The contract also outlined that if Ariel fails to receive a "kiss of true love" from Prince Eric before the sunset on the third day, she would revert to being a mermaid and belong to Ursula. Therefore, while the contract's main purpose is for Ariel to become human, the giving up of her voice is an essential aspect of the deal as well.