# Explanation

They would first meet after 24 minutes (after covering 50% of the distance represented by the circumference of the circle).

The next time they would meet would be at 72 minutes, then 120 minutes, then 168 minutes, 216 minutes and so on.

Every time they meet, they would be together and after the meeting point, they continue running in opposite directions till they meet again.

Between two meeting points, the distance between them would be 25% of the length of the circle’s circumference in two cases:

first when they are going away from each other after meeting (this would occur at a time of 12 minutes after the meeting point) and second when they are approaching each other before their next meeting (this would occur at a time of 12 minutes before the next meeting point.

The meeting times 24, 72, 120, 168, 216, 264 etc, the times at which the distance would be 25% of the circumference:  (24 –12 = 12); (24 + 12 = 36); (72 – 12 = 60);   (72 + 12 = 84); (120 – 12 = 108); (120 + 12 = 132);   (168 – 12 = 156); (168 + 12 = 180);   (216 – 12 = 204).

Only Option (d) is possible and hence is the correct answer.