Limestone is made of rock and animal shell fragments. It is an organic sedimentary rock. Organic-rich sedimentary rocks are a specific type of sedimentary rock that contains significant amounts (>3%) of organic carbon. The most common types include coal, lignite, oil shale, or black shale. The correct answer between all the choices given is the last choice or letter D. I am hoping that this answer has satisfied your query and it will be able to help you in your endeavor, and if you would like, feel free to ask another question.