The correct answer is D) well-known and respected.
The Knight is clearly admired by the host and this is emphasized by a specific use of vocabulary in this line - the verb "embark" which means not only to start something, but to start something perceived as exciting and interesting.
Moreover, he was on this journey with many notable and noble people which makes his importance and magnitude even more obvious.
"For all along the Mediterranean coast/He had embarked with many a noble host". These lines suggest that the knight is "sailing around the world". While sailing around the world, he has madeacquaintance with manyhosts who were noble and kind in nature and has made his experience and journeybetter and more fruitful. He was able to gain the best of the experiences due to the kind people who assisted him when he was in need.
