To determine which states will record fewer seismic waves, we should consider their seismic activity. Generally, California is known for its high seismic activity due to the San Andreas Fault. Nevada also experiences earthquakes, but usually at a lower frequency than California. Montana has some seismic activity, though it is less prominent than in California. New Mexico has less seismic activity compared to California and Nevada.
Based on this information, the pair that is likely to record fewer seismic waves would be "Montana and New Mexico," as both states tend to have lower seismic activity compared to California and Nevada.