Life had been mighty challenging these past years; there was no question about it,

Life had been mighty challenging these past years; there was no question about it, lizzie thought to herself as she inhaled the bracingly cold mountain air at the crest of the ski slope. she leaned forward over her poles, gazed out at the surrounding peaks, and pushed off, navigating carefully around the treacherous terrain on the steepest part of the hill. it took all of her focus and newly learned skills to negotiate the turns, but she managed it without wiping out, and emerged into the sunshine. lizzie was a senior now, and that in itself was worth celebrating—just the fact that she'd been able to remain in school. being raised by a single mom, lizzie had had to take on more than her share of running their home, sometimes missing school to take care of her little brother, gus, when they couldn't scrape the money together for a babysitter. more than often, there wasn't enough time left in the evening to do her homework, after doing the laundry and making dinner. her mom worked two jobs and often didn't even make it home until lizzie and gus were sound asleep. though she loved her family with all her might, lizzie often felt they were keeping her from the life she was meant to have. then, one day last year, she had joined a friend on a school ski club trip—the students got major discounts on tickets and equipment, so lizzie could actually afford it. she enrolled in a lesson that day, took to it like a seal to water, and after that she was hooked. the shadowed, rough, and rocky face of the mountain had given way to a sunny stretch of fluffy powder, and lizzie could feel her muscles relax. she bent her knees, her legs responding effortlessly to the hill beneath her. this was the payoff, she thought-the joy that was hers after the weeks and months of putting other people's needs first. lizzie had mastered the sport so quickly that the ski team had recruited her, and now, there even colleges were offering her scholarships— she could hardly believe it. the only trouble was, the school she'd set her sights on was two states away. her mother would never go for it; yet lizzie wondered how she could know that for sure if she didn't ask? she could've taken the open slope all the way down to the lodge, but lizzie opted at the last minute to do the more challenging route, taking a narrow path through a dark swath of trees. as she entered the mini forest, her heart pounded, as she had no idea what was around the next bend. but whatever it was, lizzie somehow knew she could handle it. she'd come this far—nothing was going to stop her now.
in this allegorical story, what most likely symbolizes lizzie's fears about the unknown?
a. the bracingly cold air b. the dark patch of trees c. the sunny stretch of snow d. the steep terrain at the top