Organic sedimentary rocks are formed from the remains of living organisms.
Over time, the remains of plants and animals can accumulate in layers and become buried by sediment. As more sediment accumulates on top, the pressure and temperature can cause the remains to compact and cement together, forming rock.
Examples of organic sedimentary rocks include coal, which is formed from the remains of ancient plants, and limestone, which can contain the remains of marine organisms like shells and coral.
Therefore, the correct answer to the question is that organic sedimentary rocks are formed from the remains of living organisms.