The a main argument put forth by advocates of the single-tax movement was that: 

a. Taxing only income would make for a more equal society.

b. Taxing only land would be very efficient because taxing land does not decrease its supply.

c. Taxing only imports would help to protect local jobs and stimulate local entrepreneurs.

d. Having only one tax would be much easier for people to understand and much less costly to administer than our current system with its wide variety of taxes.