Answer:
B . a belt of dry, high-pressure air.
As the hot air rises near the equator, it cools and loses moisture through condensation, creating a belt of dry, high-pressure air. This dry air then descends back toward the Earth's surface in the subtropical regions, around 30 degrees latitude north and south of the equator. As it descends, it warms up and creates an area of high pressure, resulting in clear skies and limited precipitation in these regions.
Option A, a belt of moist, low-pressure air, is not correct because the rising hot air cools and loses moisture, leading to dry conditions in the descending region.
Option C, the jet stream, is a high-altitude fast-flowing air current, not directly related to the process described in the question.
Option D, a Chinook, refers to a warm and dry wind that occurs on the leeward side of a mountain range, which is not directly related to the described process of hot air rising from equatorial regions.