What business category is the Yelp business which got the most 5 star reviews in?
business category refers to category_name; most 5 star reviews refers to MAX(COUNT(category_name WHERE star_reviews = 5));
SELECT T1.category_name FROM Categories AS T1 INNER JOIN Business_Categories AS T2 ON T1.category_id = T2.category_id INNER JOIN Business AS T3 ON T2.business_id = T3.business_id INNER JOIN Reviews AS T4 ON T3.business_id = T4.business_id WHERE T4.review_stars = 5 GROUP BY T1.category_name ORDER BY COUNT(T1.category_name) DESC LIMIT 1