On April 1, Owner and Buyer signed a writing in which Owner, "in consideration of $100 to be paid to Owner by Buyer," offered Buyer the right to purchase Greenacre for $100,000 within 30 days. The writing further provided, "This offer will become effective as an option only if and when the $100 consideration is in fact paid." On April 20, Owner, having received no payment or other communication from Buyer, sold and conveyed Greenacre to Citizen for $120,000. On April 21, Owner received a letter from Buyer enclosing a cashier's check for $100 payable to Owner and stating, "I am hereby exercising my option to purchase Greenacre and am prepared to close whenever you're ready." Which of the following, if proved, best supports Buyer's suit against Owner for breach of contract? 
Buyer was unaware of the sale to Citizen when Owner received the letter and check from Buyer on April 21. On April 15, Buyer decided to purchase Greenacre, and applied for and obtained a commitment from Bank for a $75,000 loan to help finance the purchase.  When the April 1 writing was signed, Owner said to Buyer, "Don't worry about the $100; the recital of  $100 to be paid' makes this deal binding."  Owner and Buyer are both professional dealers in real estate.