James Reston offered, via letter, to sell his mountain cabin to Jennifer Olsen for $375,000. Before Jennifer could respond, Reston died suddenly. What happens with the offer?​ a. ​The offer terminated with Reston's death. b. ​The offer is enforceable against the estate of Reston. c. ​The offer remains open until Reston's estate revokes it. d. ​Jennifer still has the power of acceptance for a reasonable period of time after Reston's death.