Under feudalism, which group was responsible for ruling different regions of a country

   Lords

Explanation:  Feudalism was typical of the Middle Ages, as a hierarchy stemmed from the needs and social relations in the atmosphere of influence and domination of the Church. Thus, at the very top was the king who usually exercised strong political ties with the Pope and the Church, while within the kingdom there were many possessions, feuds, administered and ruled by the nobility known as the lords. Feud was a big property of a nobleman who, on account of the need to protect and maintain order, employed knights, who could also be part of the estate, but were hierarchically under the nobility. Then, the level below in the hierarchy of this same feud were the peasants who worked there, lived and founded their families.