MrSmith Awakens One Morning to the Sound of Construction in His

Mr.Smith awakens one morning to the sound of construction in his back yard.When he looks out the window,he sees Ajax Construction Co.apparently erecting a garage on his property.He had not spoken or contracted with Ajax for this service.However,Mr.Smith really wanted a new garage,so he let them continue.Later,it was discovered that the garage was intended to go next door.Ajax sues Mr.Smith for the value of the garage.What is the probable result?

A) Ajax wins; this is a case of a contract implied-in-fact,and Mr. Smith implicitly agreed to pay for the garage.
B) Smith wins; there was no contract upon which Ajax could recover,and people are not liable for benefits that are thrust upon them.
C) Ajax wins; although there is no real contract,this is a case of unjust enrichment,and because Mr. Smith accepted the garage,he must pay for it.
D) Smith wins; unjust enrichment does not apply here because Mr. Smith had no duty to tell Ajax that it had the wrong house.