On May 2, Chief Okon posted a letter offering to sell his tractor to Alabi for ₦12,000,000. Alabi received the letter on May 4 and posted a letter of acceptance on May 6. Chief Okon received the acceptance letter on May 9. Meanwhile, Chief Okon posted a letter revoking the offer on May 5, which Alabi received on May 8. On which date was a valid contract formed between Chief Okon and Alabi?
AMay 4, when Alabi received the offer
BMay 6, when Alabi posted the letter of acceptanceCORRECT
CMay 8, when Alabi received the letter of revocation
DMay 9, when Chief Okon received the acceptance letter