I think the answer is b online I found that Organic sedimentary rocks form from the accumulation and lithification of organic debris, such as leaves, roots, and other plant or animal material
Sedimentary rocks are made of smaller pieces (like sand or mud), called sediments, that pile into layers. As pressure on the sediment increases over time, minerals act like glue, cementing them into solid rock. The three main types of sedimentary rocks at Grand Canyon are sandstone, shale (or mudstone), and limestone.
