In the winter the temperatures dip below zero, so many people vacation in warmer climates.

How much clothing do you like to wear when you sleep? ... (At this time winter bags, rated to 0°F or below, can't be tested accurately using available equipment.) ... underwear and a hat is placed in the sleeping bag, which is set atop a sleeping pad in a climate-controlled chamber. ... This is a rating for a true emergency situation, not an enjoyable backpacking trip. ... for summer backpacking even though the temperature almost never dipped below freezing, and she was rarely too warm.

explanation: the line "to save the day, harry must get past a scary three-headed guard dog" from the summary best justifies the conclusion that harry potter and the sorcerer’s stone was influenced by ancient greek mythological literature. the three other choices had nothing to do with ancient greek literature - and the words "three-headed guard dog" are what makes that choice the correct answer.