An igneous rock is light in color and has extremely coarse grains. What is the most likely origin of the rock?

Light color suggests the rock is felsic, and extremely coarse grains indicate that its magma cooled very slowly. Slow cooling allows large crystals to grow and usually happens deep underground, where magma is insulated by surrounding rock. A magma chamber is therefore the most likely origin; the ocean bottom, a volcanic slope, and an island shore are surface or near-surface settings where cooling is generally faster.

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