Which of the following is NOT a terrestrial planet?

Terrestrial planets are made up of rocks or metals with a hard surface. Not all planets are terrestrial. In our solar system, Jupiter, Saturn, Uranus and Neptune are gas giants, also known as jovian planets. On Jupiter and Saturn, hydrogen and helium make up most of the planet, while on Uranus and Neptune, the elements make up just the outer envelope.

Jupiter, Saturn, Uranus and Neptune are gas giants, also known as jovian planets

Venus, Marcary, Earth and Mars are madeup of Rocks and metals and known as terrestrial planet.

Hence Answer is 4). Saturn