Problem 1-3 (LO. 2) Complete the following regarding proportional, regressive and progressive taxes. a. A tax is [Fill in the blank], if the rate of tax remains constant for any given income level. The tax is [Fill in the blank], if a higher rate of tax applies as the tax base increases. b. Select either "Regressive", "Progressive", or "Neither" to distinguish the items below. Federal gift tax    [Fill in the blank], Federal excise tax on cigarettes    [Fill in the blank], Federal individual income tax    [Fill in the blank], Federal estate tax    [Fill in the blank], 多项填空题