Mr. Smit hires Mr. Green to build a carwash for him. Mr. Smith then goes to Euorpe for 6 weeks. When he returns he finds that Mr. Green has built the carwash on the wrong property. Which of the following is true ?

Mr. Smit hires Mr. Green to build a carwash for him. Mr. Smith then goes to Euorpe for 6 weeks. When he returns he finds that Mr. Green has built the carwash on the wrong property. Which of the following is true ?