When the product demand curve is Q = 130 - 10P and price is decreased from P1 = $10 to P2 = $9, the "point" price

When the product demand curve is Q = 130 - 10P and price is decreased from P1 = $10 to P2 = $9, the "point" price elasticity of demand at the point where the price is $9 is:

a. -2.12

b. -2.25

c. -0.44

d. -1.80