"Substantial tax benefits await the self-sufficient (e.g., an individual who can repair his own automobile is better off from a tax perspective than someone who cannot). "Select the correct comment on this statement.

a. The above statement is valid, since such an individual may barter his or her services for those of another and pay no tax on the services furnished to him.

b. The above statement is valid because the concept of taxable income would exclude the benefit derived from repairing one's own automobile.

c. The above statement is valid because the form of benefit principle enables a taxpayer to exclude gains received in a certain form.

d. The above statement is false---no tax benefits await the self-sufficient