Which of the following is most likely the next step in the series?

Option (c)

Step-by-step explanation:

From the diagram attached,

First circle has 4 points on its circumference. By joining these points we get a quadrilateral inside the circle.

Second circle has 3 on its circumference. By joining these points we get a triangle inscribed in the circle.

In 3rd circle points on the circumference have been reduced again to 2. By joining these points we get a straight line.

Following the same pattern in the 4th circle we will get a single point on the circumference of the circle.

Therefore, Option (c) will be the answer.