In a bolt factory, machines \( A \), \( B \) and \( C \) manufacture respectively \( 20\% \), \( 30\% \) and \( 50\% \) of the total bolts. Of their output \( 3 \), \( 4 \) and \( 2 \) percent are respectively defective bolts. A bolt is drawn at random from the product. If the bolt drawn is found the defective, then the probability that it is manufactured by the machine \( C \) is:
