Which of the Following Contracts Would Be Void Because of Undue

Which of the following contracts would be void because of undue influence?

A) Mikhail wants Ivana to sign a contract for the sale of her apartment. He tells her that if she does not sign the contract, he will harm her son.
B) Janet owns a pair of zircon earrings. She sells them claiming they are diamonds and receives a much higher price for them.
C) Carla unknowingly sells a painting to a collector thinking it's genuine. However, the collector finds out that it actually is an imitation.
D) Gary has been the McGill family attorney for decades. When he needs investors for his business, he demands that Mr. McGill invest in the new business.