请问这句话“The DM is the yield spread over the MRR established upon issuance to compensate investors for assuming an issuer’s credit risk.”哪里错了

NO.PZ2021120102000015 问题如下 Whiof the followingstatements about cret spremeasures is most accurate? A.The is the yielspreover the MRR establisheupon issuanceto compensate investors for assuming issuer’s cret risk. B.The Z- will above the if the MRR is expecteto remain constant over time. C.The yielsprefor a corporate bonwill equto the G-spreif the government benchmark yielcurve is flat. Cis correct.Theyielspreis the simple fferenbetween a bons all-in YTM ana current on-the-run governmentbonof similmaturity, while the G-spreisinterpolation of government benchmark yiel. If the government bonyielurve is flat, these two measures will equone another. 能一下A不对的原因么

NO.PZ2021120102000015问题如下 Whiof the followingstatements about cret spremeasures is most accurate? A.The is the yielspreover the MRR establisheupon issuanceto compensate investors for assuming issuer’s cret risk.B.The Z- will above the if the MRR is expecteto remain constant over time.C.The yielsprefor a corporate bonwill equto the G-spreif the government benchmark yielcurve is flat. Cis correct.Theyielspreis the simple fferenbetween a bons all-in YTM ana current on-the-run governmentbonof similmaturity, while the G-spreisinterpolation of government benchmark yiel. If the government bonyielurve is flat, these two measures will equone another. 答案里关于C的说明不是特别理解，能再一下吗

NO.PZ2021120102000015 问题如下 Whiof the followingstatements about cret spremeasures is most accurate? A.The is the yielspreover the MRR establisheupon issuanceto compensate investors for assuming issuer’s cret risk. B.The Z- will above the if the MRR is expecteto remain constant over time. C.The yielsprefor a corporate bonwill equto the G-spreif the government benchmark yielcurve is flat. Cis correct.Theyielspreis the simple fferenbetween a bons all-in YTM ana current on-the-run governmentbonof similmaturity, while the G-spreisinterpolation of government benchmark yiel. If the government bonyielurve is flat, these two measures will equone another. https://class.pzacamy.com/qa/148134 这是助教老师今年的解答https://class.pzacamy.com/qa/98509 这是老师2022年的解答(•_•)?

NO.PZ2021120102000015 问题如下 Whiof the followingstatements about cret spremeasures is most accurate? A.The is the yielspreover the MRR establisheupon issuanceto compensate investors for assuming issuer’s cret risk. B.The Z- will above the if the MRR is expecteto remain constant over time. C.The yielsprefor a corporate bonwill equto the G-spreif the government benchmark yielcurve is flat. Cis correct.Theyielspreis the simple fferenbetween a bons all-in YTM ana current on-the-run governmentbonof similmaturity, while the G-spreisinterpolation of government benchmark yiel. If the government bonyielurve is flat, these two measures will equone another. 这道题A哪里错了

NO.PZ2021120102000015 问题如下 Whiof the followingstatements about cret spremeasures is most accurate? A.The is the yielspreover the MRR establisheupon issuanceto compensate investors for assuming issuer’s cret risk. B.The Z- will above the if the MRR is expecteto remain constant over time. C.The yielsprefor a corporate bonwill equto the G-spreif the government benchmark yielcurve is flat. Cis correct.Theyielspreis the simple fferenbetween a bons all-in YTM ana current on-the-run governmentbonof similmaturity, while the G-spreisinterpolation of government benchmark yiel. If the government bonyielurve is flat, these two measures will equone another. 请A和B