Final answer:
The statement that best completes the list is Option 3: Congress passed legislation imposing tariffs on imported beef.
Step-by-step explanation:
The statement that best completes the list is: Option 3: Congress passed legislation imposing tariffs on imported beef.
The introduction of barbed wire and windmills led to large fenced ranches, which enabled ranchers to protect their cattle and land. With the growth of cities and increased demand for beef, cowboys rounded up the cattle and drove them to shipping centers on railroad lines. However, the impact of international trade on the cattle industry is not directly mentioned in the provided information, so Option 1 is not the best statement.
Option 2 is unrelated to the topic of the cattle industry and does not fit logically in the list. Option 4 is also unrelated to the topic of the cattle industry and refers to a different historical event happening in Europe. Therefore, Option 3 is the most appropriate statement to complete the list.