Answer:
C, birch bark peelings.
Step-by-step explanation:
" Where the bark was peeling from the trunks it lifted in tiny tendrils, almost
fluffs. Brian plucked some of them loose, rolled them in his fingers. They seemed flammable, dry and nearly powdery...
Then he went back into the shelter and arranged the ball of birchbark peelings at the base of the black rock. As an afterthought he threw in the remains of the twenty-dollar bill. He struck and a stream of sparks fell into the bark and quickly died. But this time one spark fell on one small hair of dry bark—almost a thread of bark—and seemed to glow a bit brighter before it died. "
He grinds up the bark to be finer and blows on it to give it oxygen and it catches.