问题如下图：
选项：
A. 
B. 
C. 
解释：
老师好，请问这道题及解释是什么意思？咱们的视频课上有这个知识点吗？谢谢！
This ratio is effective tratio, measuring the amount of a company’s operating cash flow usefor taxes anincating a company’s efficienin tmanagement. This ratio is operating profitability ratio, measuring the operating cash flow generateaccounting for taxes aninterest anincating a company’s liquity. A is correct. This ratio is interest coverage ratio, measuring a company’s ability to meet its interest obligations anincating a company’s solvency. This coverage ratio is baseon cash flow information; another common coverage ratio uses a measure baseon the income statement (earnings before interest, taxes, preciation, anamortization). 解析题目问一个比率是用CFO+interest+tax除以interest，是个什么比率，用来衡量什么。 我们学过interest coverage ratio=EBIT/interest，分子的EBIT是NI+interest+tax，用CFO代替NI的话就是一个现金流角度的利息保障倍数，NI是企业报告的利润，不一定就是兜里实实在在的钱，而CFO是企业的现金流，比NI更能可靠衡量企业偿还利息的能力，这是一个长期偿债能力比率。所以选cfo直接取代ni？这个也假设太意外了吧。
老师问下这道题c为什么错
