单选题 Please translate the following sentence from English into Chinese(考试题型5,英译汉:此处单选为示例,考试中需自己写出翻译内容) Initial implementations of ATFM were meant to manage air traffic demand where and when it exceeded capacity of air traffic control (ATC) services. The modern concept of ATFM has evolved to facilitate the safe, orderly and expeditious flow of air traffic by not only ensuring that ATC capacity is optimized and utilized to the maximum extent possible, but also allowing the traffic demand to be compatible with ATC capacity