托业考试

根据网考网考试中心的统计分析，以下试题在2018/8/14日托业考试习题练习中，答错率较高，为：54%
【单选题】Olivia Barber is one of the ______ serving members of staff, having started at the company 17 years ago.


A．long
B．longer
C．longest
D．length