Explanation:

There are eight planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Each of these planets has its own characteristics, including the presence or absence of satellites.

Definition of a satellite:

Before we discuss which planets have satellites and which do not, let's define what a satellite is. In astronomy, a satellite refers to a celestial body that orbits around a planet. Moons are the most common type of satellite in the solar system.

Identifying the planets without satellites:

Out of the given options, only option 'B' states that Mercury and Venus have no satellites. Let's explore why this is the correct answer.

1. Earth:
- The Earth has one natural satellite, which is the Moon.
- The Moon is Earth's only satellite and has been the subject of scientific study and exploration.

2. Mars:
- Mars has two natural satellites, Phobos and Deimos.
- Phobos and Deimos are small, irregularly shaped bodies that orbit around Mars.

3. Jupiter and Saturn:
- Both Jupiter and Saturn have numerous satellites.
- Jupiter has at least 79 known satellites, including four large Galilean moons: Io, Europa, Ganymede, and Callisto.
- Saturn has at least 82 known satellites, with its largest moon being Titan.

4. Mercury:
- Mercury is the closest planet to the Sun and it does not have any natural satellites.
- This means that Mercury does not have any moons or other celestial bodies that orbit around it.

5. Venus:
- Venus is the second planet from the Sun and it also does not have any natural satellites.
- Similar to Mercury, Venus does not have any moons or other celestial bodies that orbit around it.

Conclusion:

Based on the information provided, the correct answer is option 'B' - Mercury and Venus. These two planets do not have any natural satellites, while the other options (Earth and Mars; Saturn and Jupiter; Earth and Venus) have at least one natural satellite each.