What star rating is the most common for beers containing corn syrup?
most common refers to MAX(COUNT(StarRating)); containing corn syrup refers to CornSyrup = 'TRUE';
SELECT T2.StarRating FROM rootbeerbrand AS T1 INNER JOIN rootbeerreview AS T2 ON T1.BrandID = T2.BrandID WHERE T1.CornSyrup = 'TRUE' GROUP BY T2.StarRating ORDER BY COUNT(T2.StarRating) DESC LIMIT 1