Final answer:
Large terrestrial organisms living in hot and dry climates most likely use evaporative cooling to regulate their body temperature, with elephants being a classic example.
Step-by-step explanation:
The organisms that are most likely to use evaporative cooling are B. Large terrestrial organisms living in a hot and dry climate. Evaporative cooling is an effective physiological mechanism that these organisms might use to regulate their body temperature in environments where the heat can be extreme and water is scarce.
Large organisms, in particular, benefit from this process because they have a larger surface area that can dissipate heat, though their larger mass can make overheating a greater risk if cooling mechanisms are not efficient. A classic example of an organism using this mechanism is the elephant that sweats and frequently uses water to cool itself down.