Which of the Following Is Not an Unfair Labour Practice

Which of the following is not an unfair labour practice?

A) An employer pays higher wages when he learns that a union is trying to organize his employees, with the intention of persuading the employees they don't need a union.
B) An employer threatens to have an employee fired if he joins a union.
C) A union representative threatens to have an employee beaten if he fails to join the union.
D) An employer threatens to start another business that is non-union and transfer all the work to that business.
E) An employee is required to join a union as a condition of employment.