Which of the following activities regularly conducted by a tax-exempt organization will result in unrelated business inc

[answerhappygod]

Which of the following activities regularly conducted by a
tax-exempt organization will result in unrelated business
income?
A. Selling items made by persons with disabilities as part of their
rehabilitation when the organization is involved exclusively in
their rehabilitation.
B. Operating a grocery store staffed almost entirely by persons
with mental health conditions as part of a therapeutic
program.
C. Regularly holding a casino night fundraiser that is open to the
public but staffed entirely by unpaid volunteers.
D. Selling pet boarding and grooming services to the general public
when the organization is involved in preventing cruelty to
animals.