Camila wrote a letter to Ariana offering to sell her ring at the price of RM350. According to the letter, the offer will be open until 5 August 2020. Ariana posted a letter on 27 July 2020 accepting the offer. The letter was received by Camila on 7 August 2020. On 31 July 2020, Ariana wrote another letter to Camila to cancel her acceptance and the letter reached Camila on 10 August 2020. Camila insists that there is a valid contract between them. Discuss whether any contract exists between Camila and Ariana. 20 marks