which layers are definitely made of mafic silicate minerals? layer a layers d, e, and b layer b layer c

Brief Explanations:

Mafic silicate minerals are common in the ocean - crust. Layer B appears to be part of the ocean - crust based on the geological context of the diagram, which shows a mid - ocean ridge setting. Layers D, E are likely sedimentary layers on top of the crust and layer A seems to be part of the mantle or a different geological unit. Layer C is a surface layer which is less likely to be mafic silicate minerals.

Answer:

Layer B