Explanation:

- The Arabian Sea branch of the monsoon typically hits Mumbai around early June.

- Option 1: March 10

- This is incorrect. March is typically dry in Mumbai, as it falls before the onset of the monsoon.

- Option 2: August 10

- This is incorrect. By August, the monsoon has already been active for some time in Mumbai.

- Option 3: June 10

- This is generally correct. Mumbai often sees the arrival of the monsoon around early June, sometimes even precisely around June 10.

- This is the closest to the actual timeframe.

- Option 4: September 10

- This is incorrect. By September, the monsoon is nearing its retreat phase in the region.