A provisional broker with Top Notch Realty is working with the buyer customer as a seller’s sub-agent to find a home. Top Notch Realty does not offer any form of buyer agency, dual agency, or designated agency. After the buyer finds a home with assistance of the provisional broker, the buyer submits an initial offer, using the NCAR/NCBA Offer To Purchase and Contract, on a property listed with another firm, Leading Edge Realty. After the listing agent presents the offer, the seller signs the offer with no changes. The listing agent with Leading Edge Realty immediately calls the provisional broker on his cell phone to tell him that the seller has accepted the buyer’s offer with no changes and the seller has signed it. The provisional broker with Top Notch Realty calls the buyer on their cell phone immediately stating that their offer was accepted by the seller with no changes. Later that day, the listing agent with Leading Edge Realty delivers the signed contract with all signatures to the provisional broker at his office. When did the offer become a contract?