Final answer:
The word with a positive connotation in the sentence is 'Jewel,' as it suggests value and desirability, likening the pop culture lesson to a precious item.
Step-by-step explanation:
In the sentence "The teacher taught a lesson on pop culture, which was considered the jewel in the crown of the school year," the word with a positive connotation is B. Jewel. This word conveys a sense of value, worth, and delight, suggesting that the lesson on pop culture is highly cherished and esteemed, much like a precious gem in a royal crown. Positive connotations add a favorable emotional coloring to words beyond their literal meanings, enhancing the overall sentiment conveyed by the sentence.