Legal Principle: Mere silence as to the facts likely to aff ect the willingness of a person to enter into a contract is not a fraud - unless the circumstances of the case are such that - on close examination it is found to be the duty of the person keeping silent to speak - or unless his silence is - in itself - equivalent to speech. Facts: X sells by auction to Y - a horse which X knows to be of unsound state of mind. X says nothing to Y about the horse's unsound state of mind. Give the correct answer.