If you were to walk up to Arthur Bonner and say, "Hey, Butterfly Man," his face would break into a smile. The title suits him.,and he loves it. Arthur Bonner works with the Palos Verdes blue butterfly, once thought to have died out. Today the butterfly is coming back -- thanks to him. But years ago if you'd told him this was what he'd be doing someday, he would have laughed, "You're crazy." As a boy, he used to be "a little tough guy on the streets". At age thirteen, he was caught by police stealing. At eighteen, he landed in prison for shooting a man. "I knew it had worried my mom," Bonner said after he got out of prison. "So I told myself I would not put my mom through that pain again." One day he met Professor Mattoni, who was working to rebuild the habitat  for an endangered butterfly called El Segundo blue. "I saw the sign 'Butterfly Habitat' and asked, 'How can you have a habitat when the butterflies can just fly away?'" Bonner recalls. "Dr. Mattoni laughed and handed me a magnifying glass  , 'Look at the leaves.' I could see all these caterpillars  on the plant. Dr Mattoni explained, 'Without the plant, there are no butterflies.'" Weeks later, Bonner received a call from Dr. Mattoni, who told him there was a butterfly that needed help. That was how he met the Palos Verdes blue. Since then he's been working for four years to help bring the butterfly back. He grows astragalus, the only plant the butterfly eats. He collects butterflies and brings them into a lab to lay eggs. Then he puts new butterflies into the habitat. The butterfly's population, once almost zero, is now up to 900. For their work, Bonner and Dr. Mattoni received lots of awards. But for Bonner, he earned something more: he turned his life around. For six years now Bonner has kept his promise to stay out of prison. While he's bringing back the Palos Verdes blue, the butterfly has helped bring him back, too. Bonner came to know the Palos Verdes blue after he   _  .
found the butterfly had died out won many prizes from his professor met Dr. Mattoni, a professor of biology collected butterflies and put them into a lab
Question: If you were to walk up to Arthur Bonner and say, "Hey, Butterfly Man," his face would break into a smile. The title suits him.,and he loves it. Arthur Bonner works with the Palos Verdes blue butterfly, once thought to have died out. Today the butterfly is coming back -- thanks to him. But years ago if you'd told him this was what he'd be doing someday, he would have laughed, "You're crazy." As a boy, he used to be "a little tough guy on the streets". At age thirteen, he was caught by police stealing. At eighteen, he landed in prison for shooting a man. "I knew it had worried my mom," Bonner said after he got out of prison. "So I told myself I would not put my mom through that pain again." One day he met Professor Mattoni, who was working to rebuild the habitat  for an endangered butterfly called El Segundo blue. "I saw the sign 'Butterfly Habitat' and asked, 'How can you have a habitat when the butterflies can just fly away?'" Bonner recalls. "Dr. Mattoni laughed and handed me a magnifying glass  , 'Look at the leaves.' I could see all these caterpillars  on the plant. Dr Mattoni explained, 'Without the plant, there are no butterflies.'" Weeks later, Bonner received a call from Dr. Mattoni, who told him there was a butterfly that needed help. That was how he met the Palos Verdes blue. Since then he's been working for four years to help bring the butterfly back. He grows astragalus, the only plant the butterfly eats. He collects butterflies and brings them into a lab to lay eggs. Then he puts new butterflies into the habitat. The butterfly's population, once almost zero, is now up to 900. For their work, Bonner and Dr. Mattoni received lots of awards. But for Bonner, he earned something more: he turned his life around. For six years now Bonner has kept his promise to stay out of prison. While he's bringing back the Palos Verdes blue, the butterfly has helped bring him back, too. Bonner came to know the Palos Verdes blue after he   _  .
A. found the butterfly had died out
B. won many prizes from his professor
C. met Dr. Mattoni, a professor of biology
D. collected butterflies and put them into a lab
Answer: