Oh hey guys. I'm from MN too.

swimmm I believe the answer should actually be C. The process of making magma viscous through magmatic differentiation generally leaves a lot volatiles in the magma.

Masterhat, if you knew it was first order then you already knew the rate law so you did no have to determine it, or am understanding wrong?

Does anyone have the past technical problem solving test from nationals that they would like to share? If so could you send me a pm?