Your company has just begun a new product it doesn't have enough data yet in order to estimate a demand function but the following is known initially the price was set of $8 and the resulting sales were $320 units per week hoping to increase profits magements decided to raise sales by 12$ however this reduced sales by 240 units bringing total sales to only 80 units for that week in order to evaluate further price changes management asked you to estimate the price elasticity based on this information the approximate price elasticity of demand using the midpoint method is

a. -4

b. -3

c. -2

d. -1