Advantages of urban rail transit network can be described as great capacity, punctuality, _____________and low carbon. With such advantages of urban rail transit, the city is becoming more mobile, energetic and efficient. 城市轨道交通网络的优势可以描述为大容量、准点、_____________和低碳。城市轨道交通的这些优势，使城市变得流动性更强，更加有活力，更加高效。
A、commuter rail 通勤铁路
B、no traffic jam 没有交通拥堵
C、convenience 便捷