Frida hires Gwen, a real estate broker, to find a buyer for her home. Real estate brokers only have the authority to execute a purchase and sale agreement if expressly given it, and Gwen is not. Nevertheless, a young couple is thrilled when they and Gwen sign a purchase and sale agreement for Frida's house, which is their dream home.

Is Frida liable for the purchase and sale agreement?

• Yes, due to express authority.
• Yes, due to implied authority.
• Yes, due to apparent authority.
• No, Frida is not liable.