You will be given a definition of a task first, then some input of the task.
In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.

Question: Which of Mike Hoover's films had the largest box office success? Passage:Mike Hoover is an American mountaineer, rock climber and cinematographer. He first became known for an Academy Award-nominated documentary short, Solo, in which he climbed El Capitan solo. His first major involvement in commercial film was with The Eiger Sanction (1975), in which he taught Clint Eastwood how to climb in the Yosemite valley before the film was shot in Grindelwald, Switzerland in 1974. Hoover has since been a cinematographer for the documentaries To the Ends of the Earth (1983), To the Limit (1989), The Endless Summer 2 (1994) and Zion Canyon: Treasure of the Gods. In the late 1980s, he made 18 trips to Afghanistan to shoot war footage that was later featured in a program named The Battle for Afghanistan (1987). Hoover has led various film teams all over the world, particularly in physically and politically difficult locations, such as Everest, K2, the precarious rock faces of the Eiger and the Venezuelan jungle.
Links: a. Grindelwald b. To the Ends of the Earth c. Mount Everest d. Clint Eastwood
Output:
b