Marty's home had burned to the ground. When he met with his insurance adjuster, she accused him of burning down the house and said she would have him criminally prosecuted if he didn't settle the claim for much less than the house was worth. The adjuster knew that Marty had not burned down the house. Marty agreed to the settlement.
If he changed his mind, he can probably rescind the settlement on the basis of:

A) capacity.
B) duress.
C) undue influence.
D) mistake.

B) duress.

Explanation:

"Duress" refers to the exercise of unlawful pressure by one individual upon another in order to coerce such person to act in such a way which he ordinarily will not.

Duress and undue influence are two terms that appear synonymous but actually differ. Under the latter, the act of coercion is carried out by an individual who held something in trust for other. Under duress, there exists a threat to harm, which is not necessarily true in case of undue influence.

In the given case, after Marty's house was burnt, the insurance adjuster instead of approving her claim, rather accused him of burning the house and further threatened him with criminal prosecution, if the former did not agree to much lower claim.  

In this case, Marty may rescind such previously agreed settlement on the grounds of  duress wherein, the insurance adjuster coerced and threatened him for such settlement and forcibly changed his action with the motive of deriving personal gains.

i believe that it is a 45% chance.