Using the available references, if the dry bulb temperature is 84° and the wet bulb temperature is 81°, what is the relative humidity in a cargo hold?

Correct Answer: Option D — 88%

Entering standard psychrometric tables or calculations with a dry bulb of 84°F and a wet bulb of 81°F yields a small wet-bulb depression of 3°, indicating high moisture content and resulting in a relative humidity of approximately 88% within the compartment.