Answer: Option C
Explanation: Fraudulent concealment or fraud by concealment is a deliberate concealment, omission or non-disclosure of an important fact or circumstance that one is legally bound to reveal with an intention to deceive.
Fraudulent concealment can occur when an employer knows that there is a risk of injury at work and knowingly hides the fact from a worker in the sense of employment law.
In the given case, delivery man deliberately made Millie sign without disclosing the fact that terms regarding her transfer of property is written on the other side.
Hence from the above we can conclude that the given case depicts fraud by concealment.