In a factory four machines produce the same product. Machine A produces 10% of the output, machine B, 20%, machine C, 30%, and machine D, 40%. The proportion of defective items produced by these follows: Machine A:.001; Machine B: .0005; Machine C: .005; Machine D: .002. An item selected at random is found to be defective. What is the probability that the item was produced by A? by B? by C? by D