On 7 March, Brendan sent a letter by express courier to Sydney offering to buy fabric from Steven. At the foot of the letter he added: 'Please write and return by express courier whether you accept my offer.:' The letter was delivered to Steven on 8 March, and he wrote accepting the offer. However, instead of giving the letter to the express courier, Steven sent it by post. An express courier letter would have arrived back in Melbourne on 9 March, but the letter of acceptance did not arrive until 12 March. On 15 March, Brendan replied to Steven's letter saying that he had bought his requirements of fabric elsewhere. Steven claimed that there had been a breach of contract. Advise Brendan as to his legal position. List and explain the main rules relating to an offer. Explain what an offer is