<em>The correct option is B) the total variety of organisms on Earth</em>
Explanation:
Biodiversity can be described as the diversity or variety of life present on Earth. The variety of plants and animals which are located in different habitats make up the biodiversity. Biodiversity is the reason that different variety exist between members of a species. Biodiversity tends to favour those organisms which are better adapted to live in an environment. These organisms tend to pass on their characteristics to their offsprings and become more in number.
The age of the solar system, derived from the study of meteorites (thought to be the oldest accessible material around) is near 5 billion years; that of the Earth is taken as 4.6 billion years. The oldest rocks on Earth are dated as 3.8 billion years.