In a factory, two machines $M1$ and $M2$ manufacture $60\%$ and $40\%$ of the autocomponents respectively. Out of the total production, $2\%$ of $M1$ and $3\%$ of $M2$ are found to be defective. If a randomly drawn autocomponents from the combined lot is found defective, what is the probability that it was manufactured by $M2$?

1. $0.35$
2. $0.45$
3. $0.5$
4. $0.4$