The argument is based on the assumption that the decrease in fatalities from car and motorcycle accidents is a significant factor in the availability of donor organs for transplants. Let's evaluate each answer choice:
(A) A significant number of the organs used in transplants come from people who die in car and motorcycle accidents.
- This answer choice aligns with the assumption made in the argument. If a significant number of organs used in transplants come from accident victims, then a decrease in accident fatalities would indeed impact the availability of donor organs.
(B) The number of car and motorcycle accidents will increase significantly during the next year.
- This answer choice is not relevant to the argument's assumption. The argument is concerned with the decrease in accident fatalities, not the prediction of future accidents.
(C) No more than 10,000 people will be in need of organ transplants during the next year.
- This answer choice does not address the assumption made in the argument regarding the source of donor organs. It focuses on the demand for transplants, not the availability of donor organs.
(D) In the past, the federal government's estimates of the number of organ transplants needed during a given year have been very unreliable.
- This answer choice introduces a new issue about the reliability of government estimates but does not directly address the assumption made in the argument about the source of donor organs.
(E) For any given fatality resulting from a car or motorcycle accident, there is a hospital in the vicinity in need of an organ for a transplant.
- This answer choice is not relevant to the argument's assumption about the source of donor organs. It introduces a different consideration about the matching of fatalities to hospitals in need.
The correct answer is (A) because it directly addresses the assumption that the argument relies on, which is that a significant number of organs used in transplants come from people who die in car and motorcycle accidents. If this assumption were not true, then the argument's conclusion would be less valid.