Answer:
Relationship by assumed representation.
Step-by-step explanation:
A third party believes a principal has an agent acting on his behalf and interests without properly confirming from the principal, this relationship is known as relationship by assumed representation.
First, the third party is not told by the principal that a particular person is his agent and will represent him, he assumes it, probably because he sees both of them together.
The third party fails to explicitly ask the principal if the agent represents his interests and goes ahead to deal with the agent, he is merely transacting based on assumed representation.
It is totally different when the principal explicitly tells the third party that this is his agent who will be representing him.