On February 2021. Abrazy itd sent an offer by letter to buy fivezer Pty Ltd's patent on new medicine to fight COMID-19. Fivezerty to received Aitra-z Pty ta'sitter on February 2021. On 8 February 2021, Astraptyita telephoned Fivezer Pty Ltd to tell them that they wete with wing their offer. On 11 February 2021 Fiere Pytta bostedsletter to Astra. Pty Ltd accepting the original offer Which of the following is correct? Select one No contract arose since Aitra-z Pty Ltd effectively revoked the offer on 8 February 2012 b. Astra-z Pty Ltd's withdrawal of the offer was ineffective as it was not in writing Since Fiverer Pty itd used the same means of communication Astra-z Pty Ltd offer was effectively accepted when Fiveter Pty Ltd posted its acceptance letter d. Astra-Z Pty Ltd's offer was an irrevocable offer and so a binding contract existed between Astra z Pty Ltd and Fivezer Pty Ltd Astra Z Pty Ltd was unable to withdraw their original offer by telephone their withdrawal was thus ineffective