问题如下图：
选项：
A. 
B. 
C. 
这里指低信用评级还是低利率啊？怎么区分？ 解释：
NO.PZ2015121810000038问题如下 ring economic periowhen sprea between corporate angovernment bon are narrowing, ansprea between higher- anlower-ratecorporate boncategories are also narrowing, it cexpectethat: A.government bon will outperform corporate bon.B.lower-ratecorporate bon will outperform higher-ratecorporate bon.C.higher-ratecorporate bon will outperform lower-ratecorporate bon.B is correct.When sprea are narrowing, investors seem to less scerning between issues with weversus strong cret, anthe rate of improvement will tento greater for those bon issueentities with a relatively weaker ability to pay. Thus, ring times when corporate bonsprea are narrowing relative to government bon, anthe sprea between higher anlower rateboncategories also narrowing, corporate bon will generally outperform government bon, anlower ratecorporate bon will tento outperform higher ratecorporate bon. 考点Cret-risky bon解析公司债与国债sprea小、评级高的债券与评级低的债券的sprea小，都可以推断出经济正在变好。经济变好时，公司债的业绩好于国债，低评级债券的业绩好于高评级债券。备注rate评级，rate-利率。所以high ratebon的是高评级债券，high rate bon high yielbon的是高利率债券（又叫垃圾债）。现在国内经济很差，但信用利差也在收窄，集体下了很多，这个怎么呢？
NO.PZ2015121810000038 如题 请回答一下谢谢
请问老师，怎么理解这里的OUTPERFORM，知道经济好的时候选择评级低的债券，但是和这里的OUTPERFORM有什么关系，谢谢老师！
outperform指的是债券价格问更高吧？
