A major issue associated with using an estimated sample regression function for forecasting a value of the dependent variable beyond the boundaries of the sample used to estimate the equation is that:

a$.$ the forecast will not have minimum variance

b$.$ the forecast will be biased

c$.$ the standard error of the forecast will grow markedly the further the respective values of the independent variables are from their sample means

d$.$ the ability to derive a precise forecast of the dependent variable falls quickly the further the respective values of the independent variables are from their sample means

e$.$ c and d