William Jenkins and Natalie Monk owned a building in Sacramento, CA.In 1979, they leased the building to Tuneup Masters for 5 years.The lease provided that Tuneup Masters could extend the lease for an additional 5 years if it gave written notice of its intent to renew the lease by registered or certified mail at least 6 months prior to the expiration of the lease. The notice had to be given by August, 1, 1983.On July 29, 1983, the president of Tuneup Masters prepared a letter exercising the option to extend the lease.He prepared and sealed an envelope.He took the letter to the Post Office where it was certified and deposited in the mail slot.Unfortunately, the letter was never received by Jenkins and Monk.Jenkins and Monk refused to extend the lease arguing that the offer to extend the lease was not accepted.Who wins and why?