Option D: A sudden drop in the reading of the barometer is an indication that the weather will be stormy. The barometer measures atmospheric pressure, which typically decreases before a storm due to the low-pressure system associated with stormy weather. A sudden drop in pressure suggests that a rapidly intensifying low-pressure system, such as a cyclone or storm front, is approaching. This drop indicates unstable atmospheric conditions, often leading to precipitation, strong winds, and turbulent weather patterns associated with storms. Option A (stable and calm weather) is unlikely because a sudden drop in pressure signifies changing atmospheric conditions, while option B (rainy weather) could occur, but the focus here is on the broader implications of stormy weather. Option C (cold weather) is not necessarily correlated with a sudden drop in pressure; cold fronts may cause pressure changes, but they don’t always result in stormy conditions. Therefore, a sudden drop in the barometer reading is a reliable indicator of impending stormy weather, characterized by turbulent atmospheric conditions, precipitation, and strong winds.