Answer:
D - The conflict between a knight's duties to his lord and his lady
Many medieval poems, particularly those from the chivalric tradition, often explore the theme of the conflict between a knight's duties to his lord (feudal obligations and loyalty) and his lady (courtly love and romantic ideals). This theme is a central element of many Arthurian legends and chivalric romances from the medieval period. It's worth noting that medieval poetry can encompass a wide range of themes, but the conflict between these two duties is a common and significant one in this genre.