Final answer:
Sue Ellen's agreement to sell the property at a lower price than asked is voidable due to the buyer's coercive threats of revealing her parents' illegal activities. The contract entered under duress gives her the right to rescind it.
Step-by-step explanation:
The agreement between Sue Ellen and the buyer is voidable. This means that Sue Ellen has the option to either enforce or rescind the contract. The contract is considered voidable because the buyer's offer was made under duress. Sue Ellen was threatened with exposure of her parents' alleged illegal activities, which is a form of coercion. In contract law, agreements entered into under duress can be invalidated because one party has been forced into the contract against their free will. Therefore, the threat of revealing illegal activities makes it voidable, not automatically void.