Suppose the income elasticity for iPads is equal to 2 then this means that
a. if income increases by $1 then the demand for iPads will increase by 2%.
b. if income increases by 2%, then the demand for iPads will decrease by 1%.
c. if income increases by 1%, then the demand for iPads will decrease by 2%.
d. if income increases by 1%, then the demand for iPads will increase by 2%.