In plant breeding programmes, the entire collection of (plant or seeds) having all the diverse alleles for all genes in a given crop is called
A. Selection of superior recombinants
B. Cross-hybridization among the selected parents
C. Evaluation and selection of parents
D. Germplasm collection

Hint: Plant breeding can be defined as the science of manipulating traits of the plant to achieve desired characteristics in the said plant. It is done to improve the quality of the plant, to yield high crops, boost superior and unique traits for agricultural use, and to improve nutritional quality in products for human use.

Complete answer: Selection of superior recombinants: Desirable homozygous individuals are sought out from a mixed group of plants. These are then multiplied in aseptic conditions to avoid any contamination. This results in the production of a new variety. This is known as the selection of superior recombinants.
Cross hybridization: New varieties of plants are established from pre-established plants. Cross hybridization involves the combination of the attribute of one plant with that of the other, which is achieved through the cross-pollination process. Wherein, the plant is fertilized by the other plant's pollen.
Evaluation and selection of parents: The desirable traits of a plant can be determined by the evaluation of the germplasm. After the evaluation, seeds of the desired plants are chosen and are then multiplied to obtain a plant of the desired traits.
Germplasm collection: Germplasm can be defined as the hereditary or genetic materials such as the seeds or tissues passed down to the offspring through the germ cells. They are collected so as to preserve the genetic information of a specific plant that can be used in the near future. These are stored in seed banks.
Therefore, based on the brief explanation provided one can conclude that in plant breeding programs, the entire collection (of plant or seeds) having all the diverse alleles for all genes in a given crop is called germplasm collection.
Hence, the correct answer is option D, i.e., Germplasm collection.

Note: For the maintenance and preservation of food security and biological diversity, germplasm collection is considered to be of great importance. They preserved a large number of genes.