To find out the change in percentage in this period over the last period, the revenue managers have to:

Select one:

a. (Total sales last period - total sales this period) / (total sales last period) = % change in sales

b. (Total sales this period - total sales last period) / (total sales last period) = % change in sales

c. (Total sale this period - total sales last period) / (total sales this period) = % change in sales

d. (Total sale last period - total sales this period) / (total sales this period) = % change in sales