Final answer:
The worship of Helios on Rhodes involved a ritual where a chariot was driven off a cliff into the sea, symbolizing devotion to the sun god.
Step-by-step explanation:
The worship of Helios, the Greek god of the sun, in Rhodes is a notable historical religious practice. The specific ritual mentioned involved driving a chariot drawn by four horses off a cliff and into the sea. This sacrificial act was a vivid demonstration of piety and dedication to the deity, signifying the power and importance of Helios in the lives of his worshippers. While not explicitly mentioned in the options provided, this act could be associated with a solar ritual, as Helios is a solar deity. However, if one needs to choose from the given options, a) Solar or b) Sun would be most appropriate, as these directly relate to Helios's domain.