Concept:A circle has infinite radii, while diameter, chord, and circumference have fixed relationships.
Explanation:- Option A is wrong: Diameter is twice the radius, not half.
- Option B is wrong: Not every chord passes through the center, so only some chords are diameters.
- Option C is correct: A circle has infinitely many radii, as any line from center to circumference is a radius.
- Option D is wrong: Circumference equals
Ï€ times the diameter, not exactly three times.
Answer:Option C is correct.