Conversation so far:
what is the difference between french and catalina dressing
Both French and Catalina dressings are oil and vinegar based, but the first has hints of mustard and seasonings while the latter's hint of tomato and spices aren't as potent.
When was the first salad dressing sold
In 1896, Joe Marzetti opened a restaurant in Columbus, OH and served his customers a variety of dressings developed from old country recipes. He began selling them in 1919.

Question: Which combination is the most popular
Self-contained rewrite: Which salad dressing is the most popular