Marble is the correct answer. When limestone, a sedimentary rock composed mainly of calcite (calcium carbonate), is subjected to heat and pressure during the metamorphic process, it transforms into marble. The metamorphism of limestone into marble involves recrystallization, where the calcite crystals in the original limestone are subjected to changes in mineral composition, texture, and structure.
The process of metamorphism typically occurs deep within the Earth's crust, where elevated temperatures and pressure lead to the alteration of existing rocks. In the case of limestone, the heat and pressure cause the calcite crystals to recrystallize into larger, interlocking crystals, resulting in the formation of marble. The color and veining patterns in marble can vary, and it is prized for its aesthetic qualities, making it a popular choice for sculpture, architecture, and decorative purposes.
Contrastingly, the other options represent different types of rocks formed through distinct geological processes: slate (Option A) is a metamorphic rock derived from shale, quartzite (Option B) forms from the metamorphism of sandstone, and granite (Option D) is an igneous rock formed from the cooling and solidification of molten magma. Thus, the correct answer is Option C, marble, when limestone undergoes metamorphism.
Therefore, the correct option is marble.