单选题：根据材料，回答题：With the unemployment rate topping 8% and the gove

根据材料，回答题：
With the unemployment rate topping 8% and the government $16 trillion in debt, it's easy to question why taxpayers are spending $ 2.5 billion on an SUV- sized Mars rover (探测车) named Curiosity, which landed successfully on the red planet in the early hours of Monday. Couldn't this money go toward something closer to home, such as providing shelter for the homeless or building roads? Yes, it could. But this kind of thinking is shortsighted.
The Mars project is the latest manifestation of America's restless desire to answer previously unanswerable questions and take on new challenges. To paraphrase President John F. Kennedy, America does things like this not because they are easy, but because they are hard.
Getting the probe down safely on Mars, after a 350 million mile journey, was certainly no easy feat. Virtually all the technology used in the approach and landing was new, or used in new ways. Once settled in, Curiosity should be a particularly awe-inspiring project. It is designed to shed light on big questions: Could life forms have ever existed on Mars? Might they still exist? And are we alone in the universe ?
When budgets are tight, space projects such as Curiosity come in for particular abuse. They are often portrayed as complicated flights of odd ideas. They are not. They are both inspirational and immensely practical. Technology is, after all, an engine of economic growth. If that is a goal, as well it should be, why not support a program that makes science exciting and showcases some of the most interesting things that. technology can do? One of the main benefits of projects like this one is to promote a confident America. Throughout history, nations that explore, and engage in science, lead the world. Beginning in the 15th century, for example, European nations sent sailors around the globe and provided the impetus for thinkers such as Copernicus, Galileo and Newton to invent modern physics and astronomy. Not coincidentally, Europe came to dominate the world until the dawn of the 20th century.
Those who would slash space program budgets apparently haven't learned history's lessons and don't see the great possibilities that the future presents--possibilities reflected in every image transmitted back from the rover.

Why is it easy to question why taxpayers' money is spent on Curiosity? A．Because Curiosity costs too much money.
B．Because the economic situation is depressed.
C．Because the money should be spent on the people.
D．Because Curiosity is meaningless and impractical.