Final answer:
The most appropriate word from the given options to describe winter temperatures in the polar zones is 'arid,' despite it usually being associated with dry conditions rather than cold temperatures. Thus (option 4) is right answer.
Step-by-step explanation:
The word that best describes the winter temperatures in the polar zones is arid (option 4). Polar zones experience extremely cold temperatures, especially in winter, with the average temperature being well below freezing.
From the options provided, 'arid' means dry, which can occur in cold regions where there is little precipitation, and is the closest to describing the low humidity, though it is more commonly associated with deserts. Thus (option 4) is right answer.
However, none of the listed options specifically refer to the cold temperatures of the polar zones. The correct term for describing the frigid temperatures of the polar zones would usually be 'polar' or 'extreme,' but since these were not offered as choices, 'arid' would be the most appropriate from the available options.