Read these sentences from the article.
At the South Pole, some scientists search for meteorites, rocks from outer space. Meteorites are no more likely to fall there than anywhere else on Earth. But, as one scientist explains, if you want to find something dark, it’s easier to look on a big white sheet.
Why does the author use the phrase a big white sheet?
A because most meteorites land at the South Pole
because big white sheets are common at the South Pole
because scientists use big white sheets to catch meteorites
because the snow that covers the South Pole is like a big white sheet