Gail owes $5,000 in unpaid taxes. Using the back of an old t-shirt, she exe- cutes an instrument for $5,000 that otherwise meets the requirements for negotiability. This instrument is most likely

a. negotiable.
b. nonnegotiable, because an instrument must be on paper.
c. nonnegotiable, because a t-shirt is not sufficiently permanent.
d. nonnegotiable, because the government does not appreciate it.