Final answer:
The Arabian Peninsula is best described as arid, with predominantly hot and dry conditions, aside from a few regions like Yemen that have more agricultural activity due to higher precipitation.
Step-by-step explanation:
The statement that best describes the Arabian Peninsula is D: Almost all of the Arabian Peninsula is arid. The peninsula experiences hot temperatures, very little rain throughout the year, and is mostly characterized by its desert environment. Regions such as the Rub' al-Khali or the Empty Quarter are extremely dry and sparsely inhabited.
Nevertheless, there are exceptions like Yemen, where mountainous regions allow for terraced farming and more agricultural productivity due to higher levels of precipitation.
However, these are small exceptions to the overall arid climate that dominates the peninsula.