Question #N256

For centuries, people have believed that the earth is flat. The first people who challenged this idea were those who dared to travel long distances, as sailors who circumnavigated the globe, or explorers who traveled to distant lands. However, the evidence was still inconclusive, and many people continued to hold onto the old world view. It wasn’t until the advent of space travel that the earth’s spherical shape became undeniable. The text emphasizes that ______

What is the most likely reason why the author uses the word "undeniably"?
A. to describe the beauty and wonder of the earth.
B. to highlight the impact of scientific discovery.
C. to indicate that the earth is a sphere.
D. to argue that the earth is flat.