If the length of the longest chord of a certain circle is 24, what is the radius of that certain circle?
Choose the correct choice from the following options.
A) 12 B) 5 C) 10 D) 15 E) 20

Rationale: "longest chord of a circle is the diameter of the circle diameter = 2 * radius if diameter of the circle is given as 24 = 2 * 12 so radius of the circle = 12 correct answer - a"
Answer: A