The output if month = 9 and day = 21 is Second half of the month.
How the output is determined:
The code block checks if the month equals 9 and accepts it.
It then checks if the day is greater than 15.
Given month = 9, which is September
Given day = 21, which comes after 15 but before 22.5 or 23, which is the third quarter of the month.
Since 21 is greater than 15, the output = Second half of the month.
Thus, the output will print Second half of the month.