Because elasticity is a units-free measure of the responsiveness of the quantity demanded of a good or service to a change in its price, __ A. elasticity is equal to the slope of the demand curve B. we can compare the responsiveness of the same good when quantity is measured in different units, or we can compare across different goods C. elasticity is dependent on the units in which the variable is measured D. elasticity is equal to the negative of the slope of the demand curve

## Step 1<br />The problem is about understanding the concept of elasticity in economics. Elasticity is a measure of how much the quantity demanded of a good responds to a change in its price. It is a unit-free measure, meaning it does not depend on the units in which the variables are measured.<br /><br />## Step 2<br />Option A suggests that elasticity is equal to the slope of the demand curve. This is not correct because the slope of a demand curve is a ratio of the change in quantity to the change in price, which is not the same as elasticity.<br /><br />## Step 3<br />Option B suggests that we can compare the responsiveness of the same good when quantity is measured in different units, or we can compare across different goods. This is correct because elasticity is a unit-free measure, meaning it does not depend on the units in which the variables are measured.<br /><br />## Step 4<br />Option C suggests that elasticity is dependent on the units in which the variable is measured. This is not correct because elasticity is a unit-free measure, meaning it does not depend on the units in which the variables are measured.<br /><br />## Step 5<br />Option D suggests that elasticity is equal to the negative of the slope of the demand curve. This is not correct because the slope of a demand curve is a ratio of the change in quantity to the change in price, which is not the same as elasticity.