Why Lightning energy is a fast, high-current impulse, so a tower needs a low-impedance path to earth at every leg, not one long skinny path. Standard practice (and the National Electrical Code) calls for full-length eight-foot ground rods at each leg, all bonded together and to the tower with heavy conductor, and then bonded back to the station's service ground so everything rises and falls in voltage together. Short rods or a single rod leave too much resistance and too much inductance to carry a strike safely.
Watch out A cold-water pipe connection is not acceptable as the tower ground (modern plumbing is often plastic or has non-conductive joints), and an RF choke does nothing for lightning, which is DC-to-low-frequency impulse energy that a choke cannot pass to earth.
Eight feet, every leg, all bonded. If the answer says one rod, four feet, or a water pipe, it's wrong.