The correct answer is A) Tom.
Tom is committing sexual harassment, although Rebecca never noticed the gesture or hears about it.
Tom has to be careful and does not show this kind of conduct in the workplace because if someone reports him, he could be in trouble. Thus type of harrasment has created many problems because it represent an offense to the other person. It could happen in the workplace, the church, social club, in athletics, every where. So, stay out of it. Remember that sexual harrasment is ilegal.