Three factories produce phone chargers to supply the market. Factory A produces 20%, 40% of the tools are produced in factories B and 40% in factory C. 5% of the chargers produced in factory A, 2% of the chargers produced in factory B and 3% of the chargers produced in factory C are defective. A charger is selected at random in the market and found to be defective. what is the probability that this charger was produced by factory B? 0.267 a. b. 0.286 0.278 0.020 0.040