Answer:
a. undue influence.
Explanation:
Undue influence -
It the case , when the person is capable to persuade some other person's decision because of the link between the two parties , is known as undue influence .
In most of the case , one of the party is in power with respect to the other party , which can be due to more education , elevated status , emotional connections .
And , due to this advantage , the more powerful person uses this advantage .
Hence , from the question , Mona may rescind the contract due to undue influence .
