Concept:Sedimentary rocks form from the compaction and cementation of mineral grains or organic remains over long periods.
Explanation:Coal is an organic sedimentary rock.
It develops from thick layers of dead plant material that are buried, compressed, and slowly converted into carbon-rich deposits.
Gneiss is a metamorphic rock formed when existing rocks are subjected to intense heat and pressure.
Granite is an igneous rock that crystallises from molten magma below the Earth's surface.
Marble is also a metamorphic rock, produced when limestone undergoes heat and pressure.
Therefore, only coal fits the definition of a sedimentary rock.
Answer:A. Coal