问题如下图：
选项：
A. 
B. 
C. 
解释：
老师这个为什么不是C ? 考虑的时候是用 （假设）（1+S4）^4=（1+S2）^2*（1+f(2,2)）^2 这类公式吗？如果是upward sloping 的话 应该是f(2,2)>S4吧？老师我这个思考逻辑是不是有问题。所以我没有选答案A，劳烦老师告诉正确的思考方式，谢谢！
NO.PZ201712110200000105 问题如下 Liz Tyo is a funmanager for actively manageglobfixeincome funthbuys bon issuein Countries anShe anher assistant are preparing the quarterly markets upte. Tyo begins the meeting stributing the ily rates sheet, whiinclus the current government spot rates for Countries anC shown in Exhibit 1.Exhibit 1.₤Toy’s Government Spot RatesTyo asks her assistant how these spot rates were obtaine The assistant replies, \"Spot rates are terminethrough the process of bootstrapping. It entails backwarsubstitution using pyiel to solve for zero-coupon rates one one, in orr from latest to earliest maturities.\"Tyo then provis a review of the funs performanring the last yeancomments, \"The choiof appropriate benchmark pen on the country’s characteristics. For example, although Countries A anB have both active government bonmarket ana swmarket, Country C’s private sector is mubigger thits public sector, anits government bonmarket lacks liquity.\"Tyo further points out, \"The funs results were mixe returns not benefit from taking on aitionrisk. We are especially monitoring the riskiness of the corporate bonholngs. For example, our largest holngs consist of three four-yecorporate bon (Bon 1, 2, an3) with inticmaturities, coupon rates, another contraterms. These bon have Z-sprea of 0.55%, 1.52%, an1.76%, respectively.\"Tyo continues, \"We also look risk in terms of the swsprea We consirehistoricthree-yeswsprea for Country whireflethmarket’s cret anliquity risks, three fferent points in time.\" Tyo provis the information in Exhibit 2.Exhibit 2 SelecteHistoricThree-YeRates for Country BTyo then suggests ththe firm wable to a return ring the yielcurve. The funplans to continue to use this strategy but only in markets with attractive yielcurve for this strategy.She moves on to present her market views on the respective yielcurves for a five-yeinvestment horizon.Country \"The government yielcurve hchangelittle in terms of its level anshape ring the last few years, anI expethis trento continue. We assume thfuture spot rates reflethe current forwarcurve for all maturities.\"Country \"Because of recent economic tren, I expea reversin the slope of the current yielcurve. We assume thfuture spot rates will higher thcurrent forwarrates for all maturities.\"Country \"To improve liquity, Country C’s centrbank is expecteto intervene, leang to a reversin the slope of the existing yielcurve. We assume thfuture spot rates will lower thtoy’s forwarrates for all maturities.\"Tyo’s assistant asks, \"Assuming investors require liquity premiums, how ca yielcurve slope wnwar Whes this imply about forwarrates?\"Tyo answers, \"Even if investors require compensation for holng longer-term bon, the yielcurve cslope wnwarfor example, if there is expectation of severe flation. Regarng forwarrates, it chelpful to unrstanyielcurve namicalculating implieforwarrates. To see whI mean, we cuse Exhibit 1 to calculate the forwarrate for a two-yeCountry C lobeginning in three years.\"Baseon Exhibit 1 anTyo’s expectations, whicountry’s term structure is currently best for trars seeking to ri the yielcurve? A.Country B.Country C.Country A is correct. Country A’s yielcurve is upwarsloping—a contion for the strategy—anmore so thCountry B’s. C是怎么体现出来YielCurve不是stable的呢？是因为政府实施了干预？C后半句说的Future Spot Rate小于ForwarRate说明就是一个向上倾斜的曲线，不太明白助教之前的回答，烦请老师一下可以吗?
NO.PZ201712110200000105 C国为什么不选呢？经过政府干预后不也恢复正常了吗？spot rate比forwarrate不就是正常的吗？
这道题说future spot rate reflethe forwarrate，意思是不是在说yielcurve is stable？
每次遇到这种题都错，分不清楚，是哪个知识点理解的不对呢？
为什么不选B呢？
