The line passing through the point of contact is called the NORMAL to the circle at the point  of contact.

Explanation:

A circle is a closed figure with all points equidistant from a fixed point called the center. The circle is divided into several parts, and each part has its significance. A line is a straight path that extends infinitely in both directions. When a line intersects the circle, it creates several geometric figures such as tangents, chords, secants, etc.

A tangent is a line that touches the circle at only one point and is perpendicular to the radius at that point. A tangent is always drawn from an external point, and it never intersects the circle. The point where the tangent touches the circle is known as the point of contact.

A chord is a line segment that connects two points on the circle. A chord can be drawn from any point on the circumference of the circle, and it divides the circle into two parts.

A normal is a line that is perpendicular to a tangent at the point of contact. The normal is drawn from the center of the circle to the tangent.

In this question, we are given that a line passes through the point of contact and the center of the circle. Such a line is called a normal.

Therefore, option C is the correct answer.

Conclusion:

A normal is a line that passes through the center of a circle and is perpendicular to the tangent at the point of contact. A normal is an essential concept in geometry, and it has several applications in different fields.