Final answer:
Over the past 10 years, 1,3-butadiene has ranked 38th among the top 50 industrial chemicals. It is primarily used for the production of synthetic rubber.
Step-by-step explanation:
The 1,3-butadiene, an important unsaturated hydrocarbon used in the manufacture of synthetic rubber, has maintained a specific position in the top 50 industrial chemicals over the past decade. Its rank among these chemicals is not the highest, yet it's significant due to its applications. When looking at the options provided, we can determine that the correct answer to the question is (c) 38th.