12-year-old John Thomas Robertson is a born train fan. "I've liked trains probably from the day I was born," he told Good Morning America. "When I was very little," he said, "my grandpa got me a train model. I would just watch it go round for hours and hours." When Robertson finally had the opportunity to ride on a train, he felt great. His journey was so _ that he couldn't keep it to himself: he decided to take all his classmates to go on a ride with him. When he found that some of his classmates couldn't pay the fare, he collected cans   and bottles and raised more than $1,000 for them. That trip was such a happy one that he made it a yearly action. "It never gets boring for some reason; it's just fun," he said. "It really lets people get away from their busy life and have fun. Every October, Robertson takes a new group of children to ride on the train --but now, he has a problem. Several disabled children were refused because the train was not accessible   to disabled people. "He was angry to think that children of his own age couldn't ride a train," his mother said. But he wouldn't say no: he recently sent a letter to the train office for help. To his surprise, the leader, Ty Pennington, accepted the letter in person. He said that he and his workers would work on making a train accessible to disabled people. The disabled children were refused to get on the train because   _  .
the trains then weren't accessible to the disabled Robertson had not saved enough money for the tickets they couldn't afford the train tickets the driver would not allow them to do so
Question: 12-year-old John Thomas Robertson is a born train fan. "I've liked trains probably from the day I was born," he told Good Morning America. "When I was very little," he said, "my grandpa got me a train model. I would just watch it go round for hours and hours." When Robertson finally had the opportunity to ride on a train, he felt great. His journey was so _ that he couldn't keep it to himself: he decided to take all his classmates to go on a ride with him. When he found that some of his classmates couldn't pay the fare, he collected cans   and bottles and raised more than $1,000 for them. That trip was such a happy one that he made it a yearly action. "It never gets boring for some reason; it's just fun," he said. "It really lets people get away from their busy life and have fun. Every October, Robertson takes a new group of children to ride on the train --but now, he has a problem. Several disabled children were refused because the train was not accessible   to disabled people. "He was angry to think that children of his own age couldn't ride a train," his mother said. But he wouldn't say no: he recently sent a letter to the train office for help. To his surprise, the leader, Ty Pennington, accepted the letter in person. He said that he and his workers would work on making a train accessible to disabled people. The disabled children were refused to get on the train because   _  .
A. the trains then weren't accessible to the disabled
B. Robertson had not saved enough money for the tickets
C. they couldn't afford the train tickets
D. the driver would not allow them to do so
Answer: