OLM animated Pokémon: The First Movie.
The Japanese studio, whose name is commonly expanded as Oriental Light and Magic, produced the film as part of its work on the Pokémon anime. Kunihiko Yuyama directed the movie, while the screenplay was written by Takeshi Shudo.
OLM had already been producing the television series, so the film extended the established anime's characters, designs, and world onto the cinema screen. The movie's main story focuses on Mewtwo, clones, identity, and the consequences of treating living creatures as tools.
The studio is sometimes confused with distributors or franchise owners. Toho distributed the Japanese film, while The Pokémon Company oversees the broader brand. OLM's role was animation production, making it the correct answer for the studio question.