What mapping technician helps in
the earth's surface.

Mapping technicians collect data and make maps of the Earth's surface. They both assist surveyors, and cartographers and photogrammetrists.

I guess you haven't included the last sentence of this excerpt: "But the thought of a mad cow epidemic still keeps Hughes awake some nights." This sentence is crucial, and it confirms that the correct answer is C. Another mad cow disease outbreak is possible.

Explanation:

From the excerpt, it's obvious that this disease is both very dangerous, highly infectious, and extremely difficult to prevent. The tone doesn't suggest that the US is now free from the disease. On the contrary, it reinforces the possibility of a new outbreak. Also, the passage is not about Hughes's and his team's stellar accomplishments or dreams of fighting epidemics. In fact, they barely managed to contain the disease. The article is about a problem and a solution, and not the team of experts and their professional struggle or mission.