解析: 细节理解题。文中第四段提到了Henry,他是前塔斯基吉空军成员,由原文“A problem arose when some white passengers were still standing, which was against the rules. Henry was put off the bus, even though he was the first person to board the bus and had paid his fare”可知,Henry是第一个上车的,并且买了车票,但是当后来有白人乘客没有座位站着的时候,他被赶下了车。按照当时的法律,他是应该给白人乘客让座的,如果让座了,就不会被赶下车。所以他是拒绝让座的。选项A正确。B、C、D均与原文不符。