A certain parking lot has three entrances. 40% of drivers use entrance 1 (A1), 35% use entrance 2 (A2), and 25% use entrance 3 (A3). Of those drivers using entrance 1, 30% park for more than two hours (event B). Of those drivers using entrance 2, 60% park for more than two hours, whereas of those using entrance 3, 50% park for more than two hours. What is the correct probability notation to represent 40%