Final answer:
Neptune is the coldest planet among the given options, which include Earth, Jupiter, and Uranus.
Step-by-step explanation:
Among the four giant planets of the solar system—Jupiter, Saturn, Uranus, and Neptune—the coldest is Neptune. Neptune is furthest from the Sun and typically has the lowest average temperature.
Uranus also has low temperatures and lacks the internal heat source that Jupiter, Saturn, and Neptune possess, but it is still warmer than Neptune. Despite being furthest from the Sun, Pluto was not listed as an option but is still colder than Neptune.