1. Grand Island Development Corporation owned several cottage lots on Vancouver Island, and on September 10 sent a letter to Onshore Construction Company offering to sell the lots for $300,000. Onshore Construction Company sent a reply by return mail on September 13 offering to buy the lots for $250,000.

Grand Island Development Corporation did not respond immediately, but a week later, on September 20, the President of Grand Island Development Corporation met the President of Onshore Construction Company at a charity dinner, at which time the President of Onshore Construction Company indicated that his company was still interested in the purchase of the cottage lots, and enquired if Grand Island Development would be willing to reduce the price of the lots. The President of Grand Island Development stated that the $300,000 price was 'firm'.

On September 23 the Onshore Construction Company sent a letter to Grand Island Development Corporation accepting its offer to sell the cottage lots for $300,000. Due to a delay in the delivery of the mail, the letter was not received at the office of Grand Island Development Corporation until September 28.

In the meantime, when Grand Island Development Corporation had not heard from Onshore Construction Company by September 26, it accepted an offer to purchase the lots from Cottage Contracting Ltd.

Identify the various rights and liabilities that arise from the negotiations.