If the amount is withdrawn at the end of each quarter, the interest is calculated on the total money withdrawn during the year, for a period of ...........

4.5 months

The correct answer is option 4- 4.5 months.

If the amount is withdrawn at the end of each quarter, the interest is calculated on the total money withdrawn during the year, for a period of 4.5 months.

Ist drawing = 30th June, so months left after it are 9.
Last drawing = 31st March, so months left after it are 0.
Average Period = (No. of months left after 1 drawings + No. of months left after last drawings)/2
                      = (9+0)/ 2
                      = 4.5 months