In which of the following situations is the agent the only liable party for the contract?

Multiple Choice

• The agent contracts with a third party through the medium of a non-negotiable instrument.
• The contract expressly includes the principal in the contract.
• The agent contracts with a third party knowing the third party would not enter into a contract with the principal if the principal's identity were disclosed.
• The third party contracts with the agent that does not require the agent's performance.