Variation in the genes of an organism within a species or between the population of same species is called

The correct option is A genetic diversity
Variation in the genes of an organism within a species or between the population of same species is called genetic diversity.
For example, there are about 1000 different varieties of Mangifera indica (mango) found in India

Species diversity refers to the variety of species in a region and is determined by its species richness (number of species present per unit area of a region). E.g: The huge variety of amphibian species found in the Western Ghats

Species richness refers to the number of different species that are found in a given ecosystem, region or an area.

Ecological diversity refers to the variety of ecosystems present in a region. E.g: India has a large variety of ecosystems such as rain forests, alpine meadows, deserts, etc.