Which models are checked for Exhaust Emissions System compliance?

The requirement to check for Exhaust Emissions System compliance applies to vehicles manufactured in 1968 and newer. This is significant because the Clean Air Act, which aimed to regulate air pollutants from vehicles, went into effect during that period. By 1968, common emissions control technologies were beginning to be implemented in vehicles, and this marked a shift toward stricter emissions standards that continued to evolve. Vehicles dating from 1968 onward are subject to inspections to ensure they meet these emissions standards, as they are equipped with systems intended to limit the release of harmful pollutants.

The other options reference models that are either too old or predates the establishment of stricter emissions regulations, which means they do not fall under the current compliance inspection requirements. Therefore, the correct focus on 1968 and newer models aligns with the legal framework governing emissions testing.