What was the number of licensed motor carriers between 1980 and 1990?

Answer: C — 40,000

The number of licensed motor carriers between 1980 and 1990 was indeed around 40,000. This figure reflects the significant growth and changes within the trucking industry during that decade, which was marked by deregulation and an increase in the number of companies entering the market. The Motor Carrier Act of 1980 played a pivotal role in deregulating the industry, which led to an influx of new carriers seeking to take advantage of more favorable operating conditions. This allowed for more competition and options in transportation services, thus contributing to the increased number of licensed motor carriers. The growth in this sector is a crucial indicator of the broader economic and regulatory trends of that era, demonstrating how legislation can influence industry dynamics. The other provided options suggest figures that do not align with the historical data showing a substantial rise in licensed carriers during this period.