Can you please explain me how to advice all of them. Please mention the issue also. thanks

Andy advertised his land for sale at $200,000 cash. Bill came to accept the offer, but told Andy he could only pay $100,000 cash and promised to pay the remaining $100,000 in two installments. Andy said nothing. Shortly after, Chan came to view the land, and told Andy that if he (Chan) hears no more from Andy by the next day, he will consider the land as his for $180,000. Andy remained silent. Later in the evening, Don comes to view the land and told Andy that $200,000 was "rather expensive". He asked if Andy would accept $150,000 cash. Again, Andy said nothing. The next day, Eric comes to view the land and after some discussion, agrees to Andy's price of $200,000. Andy sells the land to Eric for $200,000. Bill, Chan and Don each believe they have a legally binding contract with Andy, and as such are now contemplating legal action against him for breach of contract.