Gawain wear the green girdle as a symbol of weakness .
Answer: D
Explanation
Gawain had previously wore the green girdle as a symbol of survival as directed by his lover.
However, after he fails, Gawain wore the green girdle with the purpose to own his weaknesses and misdemeanour.
The green girdle was a reminder to him and everybody else that one can only forget his/her iniquities but cannot erase them.
The Knights however wore the green girdle to commemorate Gawain as a symbol of honor.
From the knight's perspective the girdle won in remembrance of Gawain doesn't symbolize failure as it did before.