问题如下：
Which of the following phenomenons is often referred to as the “peso problem"
选项：
A.Looking backward, we are likely to underestimate ex ante risk and overestimate ex ante anticipated returns.
B.Looking backward, we are likely to overestimate ex ante risk and overestimate ex ante anticipated returns.
Looking backward, we are likely to underestimate ex ante risk and underestimate ex ante anticipated returns.
解释：
A is correct.
解释：
“peso problem"通常是指在解释给定样本期间的历史价格和收益时，分析师需要评估资产价格是否反映了在此期间没有发生的非常负面事件的可能性。所以回顾过去，我们可能会低估事前风险，高估事前预期回报。所以只有A选项正确。
peso问题，是事前认为peso贬值，实现没有发生，不是高估风险吗？同时后面预计实际贬值后，收益率没有预想的高，不也是高估收益率吗？为什么不选B
