Pope agreed to sell certain land to Pelz and retained a mortgage on the property to secure payment of the purchase price. The mortgage contained a clause providing that if Pelz defaulted, Pope had the “right to enter upon the above-described premises and sell the same at public sale” to pay the balance of the purchase price, accounting to Pelz for any surplus realized on the sale. What type of foreclosure does this provision contemplate: (1) strict foreclosure, (2) action and sale, or (3) private power of sale?