单选题 Urban congestion would be greatly relieved if only the ______ charged on public transport were more reasonable.

【正确答案】 A

【答案解析】(prices价格)。句意为：只要公交车上的价格合理，都市的交通拥挤状况就可以大大地缓解。B．tickets票；C．fees费用；D．tariffs关税。