PT 7 S1 Q11

In 1990 major engine repairs were performed on 10 percent of the cars that ... ...

Which one of the following, if true, most helps to explain the discrepancy?
(A) Government motor vehicle regulations generally require all cars, whether old or new, to be inspected for emission levels prior to registration.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Practice Set: "Resolve/Explain" Questions, Set 2 - Difficult/Uncommon Mix (25Q)