In a regression of the log of consumption on the log of income, the coefficient of 1.03 means that
a. when income increases by $1, predicted consumption increases by $1.03
b. when income increases by $1, consumption tends to increase by 1.03%
c. when income increases by 1%, predicted consumption increases by 1.03%
d. when income increases by 1%, consumption tends to decrease by 1.03%