In "Nothing Gold Can Stay," why does Robert Frost allude to Eden? 
 A. Eden is a place that, like the natural world, is known to be filled with gold.
 B. Eden's short- lived perfection is similar to the temporary perfection of nature's first green.
 C. Eden is a place that Frost visited many times and came to think of as golden.
 D. Eden is a place that remained perfect forever, just like the world described in Frost's poem.