Which statement describes the u. s organ donation system?
a. it is mandatory.
b. the waiting lists for organs are very short.
c. the only types of organs that can be transplanted are kidneys and hearts.
d. transplant recipients receive organs for free.

The correct answer should be
D. Transplant recipients receive organs for free.

That's because it's not mandatory, you don't have to donate your organs if you don't want to. The lists can be very long and many people die before receiving their organ. All possible types of organs can be donated.