Which sentence from the article supports the devastation from pyroclastic flows and surges? a. "on that night an explosive eruption tore through the summit and spewed approximately 20 million cubic meters of hot ash and rocks across the snow-covered glacier." b. "these materials were transported across the snow pack by avalanches of hot volcanic debris (pyroclastic flows) and fast-moving, hot, turbulent clouds of gas and ash ( pyroclastic surges)." c. "as these floods of water descended the volcano, they picked up loose debris and soil from the canyon floors and walls, growing both in volume and density, to form hot lahars." d. "in a few short minutes most of the town was swept away or buried in a torrent of mud and boulders, and three quarters of the townspeople perished."