Which of the Following Best Describes the MAPE Measure of Forecast

Which of the following best describes the MAPE measure of forecast error?

A) Calculate the deviation between the forecast and the actual value for each period. Divide each deviation by the level of demand. Take the absolute value of each deviation, sum all values, and multiply by 100. Divide by the number of forecast errors.
B) Calculate the absolute value of the deviation of the forecast from the actual value for all periods. Sum all of the absolute values of the deviations and divide by the number of forecast errors.
C) Calculate the difference between the forecasted value and the actual value for all periods. Square each of the differences. Sum all of the squared differences and divide by the number of differences.
D) Calculate the difference between the forecast and the actual value for all periods. Sequentially sum up the forecast errors.