The east coast megalopolis faces serious problems because of

climate
water shortages
overpopulation
culture

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The east coast megalopolis faces serious problems because of water shortages.

Water scarcity is the lack of sufficient available waterresources to meet water needs within a region. It affects every continent and around 2.8 billion people around the world at least one month out of every year. More than 1.2 billion people lack access to clean drinking water.

I'm pretty sure it's c. extremely gradual but not 100% sure though.

Answer feldspar,quartz,mica and amphibole;