The marital bias in the tax law (i.e. the tax a married couple pays vs. what they would pay in total if they stayed single):

a. Is positive (i.e. less tax) if one spouse has no income.

b. Is negative if one spouse has no income.

c. Is positive if both spouses have income.

d. Is always negative if there are no children.

e. Is caused by the non-deductibility of wedding expenses.