For a Given Product Demand, the Time Series Trend Equation

For a given product demand, the time series trend equation is 53 - 4 X. The negative sign on the slope of the equation

A) is a mathematical impossibility
B) is an indication that the forecast is biased, with forecast values lower than actual values
C) is an indication that product demand is declining
D) implies that the coefficient of determination will also be negative
E) implies that the cumulative error will be negative