An income tax system is said to be progressive ________________.
if the rate of increase of the tax liability for a tax paying unit is less than the rate of increase of its income
if the rate of increase of the tax liability for the tax paying unit is greater than the rate of increase of its income
if the rate of increase of the tax liability for tax paying unit is equal to the rate of increase of its income
if the rate of increase of the tax bears a multiplicative relation with rate of increase in income of tax paying unit