A landowner and a tenant farmer are negotiating a contract. The landowner's income (economic surplus) is the total harvest minus the tenant's share. The landowner's initial offer, Allocation N, involves the tenant working 20 hours for a total harvest of 70 bushels, with the tenant receiving 30 bushels. The tenant wishes to make a counter-offer, Allocation R, where she works fewer hours. Which of the following counter-offers would the landowner be indifferent to, compared to his initial offer?