Please answer the following question: Write a multi-choice question for the following article, with the given choices and answer: Article: Bob Butler lost his legs in 1965 in Vietnam. Later he returned to the USA and began his life in wheelchair . One day he was working in his yard when he heard a woman calling for help. He began moving towards the woman's house, but something on the ground stopped his wheelchair going through the back door. So he got out of his wheelchair and started to crawl . When Butler got through the back door of the house, he found there was a little girl in the pool. She had no arms and couldn't swim. Her mother was calling for help crazily. Butler got into the pool and pulled the little girl out of the water. Her face was blue, and she was not breathing. Butler did CPR on her right away. As Butler continued doing CPR, he talked to the mother. "Don't worry," he said. "It'll be OK. I was her arms to get out of the pool. I am now her lungs. Together we can make it." Soon the little girl coughed and began to cry. The mother asked Butler how he knew it would be OK. "I didn't know," he told her. "But when my legs were blown off in the war, a little girl in Vietnam said to me in broken English, 'It'll be OK. You will live. I'll be your legs. Together we make it.' Her kind words brought hope to me and I wanted to do the same for your little girl." Options: A By bike. B On foot. C By crawling. D By moving his wheelchair. Answer: C By crawling. Question:
A:
How did Butler get through the woman's back door?