Why​ isn't elasticity just measured by the slope of the demand​ curve?
a. the slope of the demand curve changes along the curve.
b. price elasticity of demand is the same as the slope of the demand curve.
c. the measurement of slope is sensitive to the units chosen for quantity and pricemeasurement of slope is sensitive to the units chosen for quantity and price.
d. the slope of the demand curve is negative.
e. the slope of the demand curve is often unknown?