The correct answer is option 4, Slate. Shale, which is a fine-grained sedimentary rock, can undergo metamorphism and transform into slate. Metamorphism is the process where rocks undergo changes in their mineral composition, texture, and structure due to heat, pressure, and chemical reactions. When shale undergoes low-grade metamorphism, it is subjected to heat and pressure, causing it to recrystallize and transform into slate. Slate is a fine-grained metamorphic rock with distinct foliation, which means it has parallel layers or bands. It is commonly used as a roofing material due to its ability to split easily into thin sheets. Graphite (option 1) is a mineral composed of carbon and forms under different conditions. Gneiss (option 2) and marble (option 3) are also metamorphic rocks, but they are not formed from the metamorphism of shale.