问题如下图：
选项：
A. 
B. 
C. 
解释：
是否在问PV未知，怎么求debt rating ，那和credit有什么关系？谢谢
NO.PZ2016021705000023问题如下The cost of ctermineusing the yielto-maturity anthe bonrating approaches. If the bonrating approais use the:A.coupon is the yielB.yielis baseon the interest coverage ratio.C.company is rateanthe rating cuseto assess the cret fault spreof the company's bt.is correct.The bonrating approapen on knowlee of the company's rating anccomparewith yiel on bon in the public market.A是YTM的方法吗？平价发行时，YTM等于coupon？
NO.PZ2016021705000023问题如下The cost of ctermineusing the yielto-maturity anthe bonrating approaches. If the bonrating approais use the:A.coupon is the yielB.yielis baseon the interest coverage ratio.C.company is rateanthe rating cuseto assess the cret fault spreof the company's bt.is correct.The bonrating approapen on knowlee of the company's rating anccomparewith yiel on bon in the public market.这道题的c中文怎么翻译以及怎么理解？
NO.PZ2016021705000023 yielis baseon the interest coverage ratio. company is rateanthe rating cuseto assess the cret fault spreof the company's bt. is correct. The bonrating approapen on knowlee of the company's rating anccomparewith yiel on bon in the public market.这道题为什么选C呢？信用利差和rating approach有什么关系？
yielis baseon the interest coverage ratio. company is rateanthe rating cuseto assess the cret fault spreof the company's bt. is correct. The bonrating approapen on knowlee of the company's rating anccomparewith yiel on bon in the public market. 请问，B是什么中文意思？？
