Answer: The correct option is B.
Explanation: There are 2 regions of the solar system.
1) Inner region: There are 4 planets which lie in this region: Mercury, Venus, Earth and Mars. The inner region planets are rocky in nature. The orbit time of these planets around the sun is short. They have 0, 1 or 2 satellites in total. There is no ring system in these planets.
2) Outer region: There are 4 planets which lie in this region: Jupiter, Saturn, Uranus and Neptune. The outer region planets are gaseous in nature. The orbit time of these planets around the sun is long. They have usually more number of satellites around them. Ring system in these planets is very common.
Hence, Mars resides in the inner region of the solar system because it has a rocky surface that one could firmly stand on.