Question

Signals Across the Hills

[1]
In the late eighteenth century, communication over long distances was limited by the speed of a galloping horse. During the French Revolution, however, Claude Chappe and his brothers developed the semaphore telegraph, a revolutionary system of visual signaling. The system consisted of a series of towers built on high hills, each equipped with a large wooden apparatus containing two movable arms. Operators adjusted these arms using ropes and pulleys to represent different letters and symbols. These configurations could be seen from the next tower through a telescope, allowing messages to be passed rapidly from one station to the next.

[2]
The impact of this invention was immediate and profound. A message could travel from Paris to Lille—a distance of over one hundred and forty miles—in just ten minutes, a feat that previously took an entire day. By the early nineteenth century, France was crisscrossed by hundreds of semaphore towers, which provided the government with a crucial administrative and military tool. Yet, the system had significant limitations. It was useless at night or in heavy fog, and it required a massive, expensive workforce of operators who had to remain constantly vigilant.

[3]
Despite these drawbacks, the Chappe semaphore telegraph remained the gold standard of long-distance communication for decades. It was only rendered obsolete in the mid-nineteenth century with the advent of the electrical telegraph, which could transmit information instantly regardless of weather or time of day. _______________________

The writer wants to add a concluding sentence at the end of the passage (following the blank in Paragraph 3) that reinforces the historical significance of the semaphore telegraph as a precursor to modern telecommunications. Which of the following sentences best achieves this goal?