50,000 different strains of rice are example of:

Genetic diversity

The correct answer is Option (3) → Genetic diversity 

The levels of biological organisation are–

Genetic diversity : A single species might show high diversity at the genetic level over its distributional range. The genetic variation shown by the medicinal plant Rauwolfia vomitoria growing in different Himalayan ranges might be in terms of the potency and concentration of the active chemical (reserpine) that the plant produces. India has more than 50,000 genetically different strains of rice, and 1,000 varieties of mango.

Species diversity : The diversity at the species level, for example, the Western Ghats have a greater amphibian species diversity than the Eastern Ghats.

Ecological diversity: At the ecosystem level, India, for instance, with its deserts, rain forests, mangroves, coral reefs, wetlands, estuaries, and alpine meadows has a greater ecosystem diversity than a Scandinavian country like Norway.