The economy is doing badly. First, the real estate slump has been with us for some time. Second, car sales are at their lowest in years. Of course, had either one or the other phenomenon failed to occur, this would be consistent with the economy as a whole being healthy. But, their occurrence together makes it quite probable that my conclusion is correct.

Question: Which one of the following inferences is most strongly supported by the information above?
Options:
A. If car sales are at their lowest in years, then it is likely that the economy is doing badly.
B. If the economy is doing badly, then either the real estate market or the car sales market is not healthy.
C. If the real estate market is healthy, then it is likely that the economy as a whole is healthy.
D. If the economy is in a healthy state, then it is unlikely that the real estate and car sales markets are both in a slump.
E. The bad condition of the economy implies that both the real estate and the car sales markets are doing badly.
Answer: "D"