During Metamorphism, What Is the Major Effect of Chemically Active

Multiple Choice

During metamorphism, what is the major effect of chemically active fluids like water and carbon dioxide?

A) aid in the movement of dissolved ions and silicate constituents from parent minerals and facilitate growth of new metamorphic mineral grains
B) facilitate the formation of schistosity and gneissic banding in hornfels and skarns
C) increase the pressures in deeply buried, regional- metamorphic zones
D) prevent partial melting so solid rocks can undergo very high temperature regional metamorphism