How many substations does the National Weather Service receive weather data from?

The correct answer highlights the extensive network of weather monitoring and data collection that the National Weather Service (NWS) oversees. The figure of 12,000 substations refers to the various data collection points, known as Automated Surface Observing Systems (ASOS) or other similar systems, which provide critical real-time weather observations.

These substations are crucial for gathering localized weather data, including temperature, humidity, wind speed, and precipitation, which are vital for forecasting and issuing warnings about severe weather conditions. This large number of substations ensures comprehensive coverage and timely updates, allowing the NWS to deliver accurate weather information to the public and other agencies.

The other figures mentioned in the options do not reflect the current scale of the network utilized by the NWS for weather data collection, emphasizing the importance of having a significant number of substations to achieve effective weather monitoring.