Collection of plants or seeds having diverse alleles of all the genes of a crop is known as germplasm collection. It is an example of ex-situ conservation of biodiversity. Ex-situ conservation is done by preserving the components of biological diversity outside their natural habitats. It is done by conserving genetic resources, as well as wild and cultivated or species. Examples include Gene banks, Microbial cultures, Cryopreservation, etc.
So, the correct answer is 'Collection of plants or seeds having diverse alleles of all the genes of a crop'.