Final answer:
The correct option is b. In the tale 'Sir Gawain and the Green Knight,' Sir Gawain stops at a castle during his journey to find the Green Knight. This castle is a central location where major tests of Sir Gawain's chivalric virtues occur.
Step-by-step explanation:
The question refers to an event in medieval literature involving Sir Gawain, a character from Arthurian legend. Specifically, it draws upon the tale of 'Sir Gawain and the Green Knight,' where Sir Gawain accepts a challenge from a mysterious Green Knight and, after a year, embarks on a journey to find him. During his quest, Sir Gawain's stops are thematically significant and test his chivalric virtues.
One notable location Gawain visits is a castle, where he encounters the lord, Bertilak de Hautdesert, and faces various tests of his chivalry and fidelity. This castle, which seems to appear out of nowhere in the wintry landscape, becomes a crucial setting for the story's unfolding and examining Gawain's character and the chivalric code. Other locations, such as forests and rivers, are also part of the story, but it is the castle where the most significant events of the narrative take place, preceding the final meeting with the Green Knight.