Hi, sounds like it would turn into B). Metamorphic Rock. Igneous rocks are only formed when melted rock hardens and solidifies. Sediimentary rock is formed when sediment is deposited out of air, ice, wind, gravity or even water. I Doubt it would remain a sedimentary rock so the best answer would be metamorphic rock. Hope this was correct. :)
This is because the melanocytes are located in the stratum basale. Lighter-skinned people usually have low basal levels, and exposure to UV radiation causes an increase which makes skin darker.