What is the probability that it came from supplier

A company manufacturing electronic components for home entertainment systems buys electrical connectors from three suppliers. The company prefers to use supplier A because only 1% of those connectors prove to be defective, but supplier A can deliver only 70% of the connectors needed. The company must also purchase connectors from two other suppliers, 20% from B and the rest from C. The rates of defective connectors from B and C are 2% and 4% respectively. You buy one and find that it is defective. What is the probability that it came from supplier A?