Which of the following factors would primarily affect breeding system choice?

The choice that focuses on "desired breeding efficiency and control of parentage" is central to selecting a breeding system because these factors are critical in laboratory animal husbandry. When breeding animals for research, the goal is often to produce specific genetic lines that exhibit certain traits. Breeding efficiency relates to how effectively the breeding program can produce these desired outcomes within a given timeframe, while control of parentage ensures that researchers can track lineage accurately, which is vital for experiments that require genetically consistent models.

In many laboratory settings, achieving a high degree of genetic uniformity and predictability is essential for the validity of scientific studies. The breeding system chosen must therefore facilitate a structured approach to mating that maximizes the likelihood of achieving these objectives. This aspect becomes especially important in controlled breeding environments where traits need to be expressed consistently across generations for research purposes.

Other factors, such as dietary restrictions, previous breeding history, and the size of the animals, may influence management practices and animal care but are secondary to the core objectives of breeding efficiency and genetic control when determining the most effective breeding system.