Respuesta :
Answer:
The correct answer is option A. "an oath of loyalty and a pledge of military service".
Explanation:
The feudal system that prevailed during medieval Europe functioned by lords who owned pieces of land and vassals that served the lords. The responsibility of the vassal included an oath of loyalty and a pledge of military service to the lords. The oath was known as oath of fealty, from the Latin fidelitas (faithfulness), and obligated the vassal to always remain faithful to the lord.