问题如下：
Assume
that the DM country has what is considered a low-yield safe haven currency while
the EM country has a high-yield currency whose value is more exposed to
fluctuations in the global economic growth rate. All else equal, the exchange
rate for the EM currency will most likely depreciate if the:
选项：
A.long-run equilibrium
value of the high-yield currency is revised upward
nominal yield spread
between the EM and DM countries increases over time
expected inflation
differential between the EM and DM countries is revised upward
解释：
All
else equal, an increase in the expected inflation differential should lead to
depreciation of the EM currency.
解析：
real exchange rate (A/B) = equilibrium
real exchange rate + (real
interest rate B - real interest rate A)- (risk premium B - risk premium A)
根据上述公式。所以A、B选项错误。
在其它条件相同的情况下，预期通胀率的扩大会加两国的风险溢价之差，从而应会导致新兴市场货币贬值。所以C选项正确。
请问一下老师，B答案为什么不正确？nominal yield spread between the EM and DM countries increases over time ，也可以导致EM贬值吧？
