The radius of a circle is half of its diameter, so the correct answer is B (Half).

The correct answer is option 'B' - Half.

Explanation:

The radius of a circle is defined as the distance from the center of the circle to any point on its circumference. The diameter of a circle, on the other hand, is defined as the distance across the circle passing through its center and connecting two points on its circumference.

To understand why the radius is half of the diameter, let's consider a circle with a radius of 'r' and a diameter of 'd'.

- Definition of Radius and Diameter:
The radius, denoted by 'r', is the distance from the center of the circle to any point on its circumference. The diameter, denoted by 'd', is the distance across the circle passing through its center.

- Relationship between Radius and Diameter:
1. The diameter of a circle is always twice the length of its radius. In other words, d = 2r.
2. Conversely, the radius of a circle is always half the length of its diameter. In other words, r = d/2.

- Visual Representation:
To visualize this relationship, imagine a circle with a radius of 'r'. If we draw a straight line from one point on the circumference to the opposite point, passing through the center, we get the diameter 'd'. The diameter is essentially two radii placed end to end. Therefore, the radius 'r' can be seen as half of the diameter 'd'.

- Mathematical Explanation:
Let's consider a circle with a radius 'r'. The diameter 'd' is defined as the distance across the circle and can be expressed as d = 2r. Rearranging this equation, we get r = d/2. This equation shows that the radius 'r' is half the length of the diameter 'd'.

Hence, the correct answer is option 'B' - Half.