閱讀下列短文，從每題所給的四個選項(A、B、C和D)中，選出最佳選項。
Somewhere on the other side of the world, a small group of workers is busy with a life－or－death struggle．This battle isn't about self－protection, as admirable as that might be．By slaying to face the radiation and Fire at Japan's Fukushima Daiichi Nuclear Power Station following the earthquake and then tsunami(海嘯)in Japan, the 50 or so workers may have already shortened their life．They knew that would happen．
And yet they stay, working in near－total darkness, pumping seawater onto exposed nuclear fuel in hopes that they can prevent thousands of tons of radioactive material going into the air, and protect the health of millions of people．
Their task sounds like something out of a sci－fi thriller．They worked on the equipment in the complete darkness only by their flashlights, listening for explosions．They carry heavy oxygen tanks on their backs．They wear white, full－body jump suits to protect their bodies．Like Oscar said in "Armageddon"： "Scariest environment imaginable．That's all you have to say．"
According to news reports, some of the 50 workers volunteered to remain behind to take charge of the fire pumps with which they're spraying seawater on the exposed fuel．It's part of the job, part of the training, " an American nuclear power plant operator said．"Nobody makes a secret of the possible dangers at a place like this．If there's a problem, you don't call somebody in to fix it．It's our problem．We're the only ones who can fix it．That's just what we do．"
I don't know about you, but I've never really thought of nuclear power plant workers as "guardians at the gate"－those whose jobs may at any time place them in a position to protect us, perhaps at the risk of their own lives．
These are obviously guardians at the gate．In every case they're trained to respond to unknown possibilities．For them, it isn't a matter of courage－it's standard operating procedure．
