A geologist finds a metamorphic rock and notices that it has grains that formed in parallel layers. The geologist pries at the rock, and it splits apart along the bands formed by the layers.Which type of rock did the geologist most likely find?

Metamorphic rocks with mineral grains arranged in parallel layers are foliated. The fact that the rock splits along those layers supports that it is foliated; among the choices, gneiss is the foliated metamorphic rock. Marble is metamorphic but usually lacks layers, while limestone and sandstone are not metamorphic rocks.

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