A manufacturer obtains clock-radios from three different subcontractors: 10

10% from A, 20

20% from B, and 70

70% from C. The defective rates for these subcontractors are 5

5%, 4 %

4%, and 5

5% respectively. If a defective clock-radio is returned by a customer, what is the probability that it came from subcontractor A? From B? From C?