My son was a second-grader. He went to school by bus every day. He was the first student on in the morning, as we were farthest from school, and the last student off in the evening. I was a teacher myself and it was a comfort to realize the school staff   were all working as hard as I was to provide a safe learning environment. One day I came home from work and waited for my son to get home for a long time. Then I called the school. "Perhaps he's just a bit late," said the secretary. "I will call the driver to see if those children are home." A few minutes later, I answered the phone to hear that the other students were home. Then I called his friends' parents, to see if perhaps he had gotten off at their stop to play. The answers were all "No." By that time, it was dark and I was scared. My home was in the mountain areas, and it was said that a wolf had come up somewhere. My husband wasn't at home, so I forced myself to calm down and decided to go out to look for him. I was about to go out when the telephone rang; it was from the driver. "He's okay," I heard. "He was asleep on the seats in the back, under a couple of jackets. Since it's dark, can he spend the night with my family?" I was relieved and agreed. Since my son had a great adventure, the school started giving a copy of the list to the driver, so he could check off the children's names when they got off the bus. I think highly of the school for taking the cautionary   step ahead; it is a sign of their concern for students, parents, and staff. At first the secretary thought   _  .
the author's son was still at school the school bus would arrive in a while the author's son was at his friend's home there might be something wrong with the school bus
Question: My son was a second-grader. He went to school by bus every day. He was the first student on in the morning, as we were farthest from school, and the last student off in the evening. I was a teacher myself and it was a comfort to realize the school staff   were all working as hard as I was to provide a safe learning environment. One day I came home from work and waited for my son to get home for a long time. Then I called the school. "Perhaps he's just a bit late," said the secretary. "I will call the driver to see if those children are home." A few minutes later, I answered the phone to hear that the other students were home. Then I called his friends' parents, to see if perhaps he had gotten off at their stop to play. The answers were all "No." By that time, it was dark and I was scared. My home was in the mountain areas, and it was said that a wolf had come up somewhere. My husband wasn't at home, so I forced myself to calm down and decided to go out to look for him. I was about to go out when the telephone rang; it was from the driver. "He's okay," I heard. "He was asleep on the seats in the back, under a couple of jackets. Since it's dark, can he spend the night with my family?" I was relieved and agreed. Since my son had a great adventure, the school started giving a copy of the list to the driver, so he could check off the children's names when they got off the bus. I think highly of the school for taking the cautionary   step ahead; it is a sign of their concern for students, parents, and staff. At first the secretary thought   _  .
A. the author's son was still at school
B. the school bus would arrive in a while
C. the author's son was at his friend's home
D. there might be something wrong with the school bus
Answer: