Concept:Extensive goat rearing uses large grazing areas with minimal inputs and attention.
Explanation:In an extensive system, goats roam freely over vast land.
The farmer provides little feed, housing, or supervision.
This greatly reduces the amount of labour needed.
Disease control is difficult, not easy.
Goats are exposed to weather and may mate indiscriminately, but these are disadvantages.
Therefore, the main advantage is low labour requirement.
Answer:A. low labour requirement