Amar takes either a bus or a local train to work. The probability of taking a bus is 0.3 and that of taking the local train is 0.7. When he takes the bus, he is late 30% of the working days and when he takes the train it is 20% of the days. On the particular Monday, he was late for work. What is the probability that he took the bus that day?

a. 0.3
b. 9/23
c. 16/23
d. 0.7