Concept:Pen mating is a controlled natural breeding system where selected animals are kept together to mate efficiently.
Explanation:In pen mating, one breeding male is kept with one or more females in a pen.
A single male can therefore mate with many females during the breeding season.
This reduces the number of breeding males required on the farm.
As a result, the farmer spends less on feeding, housing, and caring for extra males.
Thus, the cost of keeping a breeding male becomes low.
Answer:C. cost of keeping a breeding male is low.