Here's why:
* Tethered balloons are specifically designed to carry meteorological instruments to a specific altitude, usually around 100 meters, but can reach higher depending on the balloon's size and the strength of the tether.
* Radiosondes are attached to weather balloons that are released into the atmosphere, rising to altitudes of over 30,000 meters (100,000 feet). They are not tethered.
* Weather satellites orbit the Earth, providing a broader view of weather patterns, but don't carry instruments on a tether.
Therefore, the most accurate answer is a tethered balloon.
