Final answer:
According to the doctrine of the undisclosed principal, the principal cannot be considered a party to the contract with the third party. This statement is true.
Step-by-step explanation:
True. According to the doctrine of the undisclosed principal, when someone acts on behalf of a principal (the person they represent), the principal is not disclosed to the other party in the contract. In such a situation, the third party assumes that they are contracting with the agent, not the principal. Therefore, the principal cannot be considered a party to the contract with the third party.