Table: 1996 in film
Question: Which studio has the highest return on investment for movies released in 1996 based on worldwide gross? 
Step 1 (Operation, Indexing): studio, worldwide gross
Step 2 (Operation, Grouping): studio
Step 3 (Reasoning, Aggregating): SUM, worldwide gross
Step 4 (Reasoning, Aggregating): MAX, worldwide gross
Answer: warner bros