Santino is a 31-year-old chimpanzee. He lives in a zoo. Not long ago, Santino did something surprising. Before the zoo opened, he picked up rocks and quietly put them in a pile. Once the zoo opened, he threw them at people. He seemed angry at the people watching. He tried to hit people only, not other chimpanzees. Scientists were surprised by what Santino did. They say that this shows that apes can think about the future. Santino had a ______ A. Plan B. Meal C. Meeting D. Party