Most analysts and appraisers get their equity risk premium by looking at the past: the historical risk premium is the difference between what you would have earned invested in stocks over a past period over what you would have earned on a risk free Investment, which of the following are problems with this approach? Select one: a. The estimate is subjective', since it depends upon the time perlod and averaging approach used, b. The estimate moves counter intuitively: down after crisis and up after prosperity C. The estimate is backward looking d. All mentioned e. The estimate has substantial standard error