If the ce If the of Pepsi-Cola increases from 40 cents to 50 cents per can and the quantity demanded decreases from 100 cans to 50 cans, then, (according to the arc price elasticity formula, the same formula used in class), the value of price elasticity of demand for Pepsi-Cola is
a. -0.5
b. -0.25
c. -1
d. -3
e. -2