Answer: 23.56 (choice A)
Step-by-step explanation:
Assuming each circular portion takes up 1/4 of the entire tile, this means 15/2 = 7.5 is the distance across one of the smaller sub-tiles. This is the diameter of one of the big circles.
Circumference = pi*diameter = 3.1416*7.5 = 23.562
That rounds to 23.56