Read the excerpt from the hot zone.

"there she met lieutenant colonel trotter, a stocky, dark-haired man whom nancy had worked with for many years. they put on their inner gloves and taped their cuffs. nancy put a pair of hearing protectors over her ears. she had started wearing them a while back, when people had begun to suspect that the roar of air in your suit might be loud enough to damage your hearing. they hauled on their space suits and sealed the ziploc zippers. they edged around each other as they fiddled with their suits. people wearing biohazard space suits tend to step around one another like two wrestlers at the beginning of a match, watching the other person's every move, especially watching the hands to make sure they don't hold a sharp object. this cringing becomes instinctive."

which best states the central idea of this excerpt?

(a) extreme precautions must be taken when dealing with potentially hazardous materials.

(b) it is always necessary to work with a partner when dealing with unidentified substances.

(c) scientists are well known for being overly cautious and for taking unnecessary safety measures.

(d) it is standard procedure to wear both space suits and hearing protectors in laboratories.