Mark is a sole proprietorship trading as Mark General Dealers. Last week he displayed a funky leather jacket in his shop window, with the price marked on it as K5000.00. When Peter visited the shop and expressed interest in buying the jacket for K3000.00, Mark stated that he could only reduce the indicated price to K4000.00. But Peter insisted that he was only willing to pay K3000.00 and left the shop. Peter could not however resist the temptation to buy the jacket. Barely five minutes after he had left, Peter returned to the shop to buy the jacket for K4000.00. But Mark refused to sell it, stating that he had just realized that the jacket was in fact worth more than the price marked on it. In the meantime, James also visited the shop and expressed interest in buying the jacket for the price marked on it. Mark refused to sell it to him. Advise Peter and James whether Mark owes them any contractual obligation, with reference to Zambian cases