generate questions: Its counties of Los Angeles, Orange, San Diego, San Bernardino, and Riverside are the five most populous in the state and all are in the top 15 most populous counties in the United States.
Orange, San Diego, Riverside and San Bernardino make up four of the five counties. What is the name of the last county? {sep_token} What country are all the counties in? {sep_token} What are Los Angeles, Orange, San Diego, San Bernardino and Riverside? {sep_token} What is the lowest ranking one of the counties could have in terms of most populous counties in the United States? {sep_token} What is the smallest geographical region discussed? {sep_token}