Answer:
b. Graded bedding is found as a result of underwater landslides. The presence of marine fossils confirms that the area was under the sea at one time.
Explanation:
Firstly, limestone are sedimentary rocks composed of calcium carbonate. Limestone are majorly found in marine habitat and are formed from the remains of organisms like corals, algae, and shells
From the question the limestone are formed in a marine environment and highly fossilize. Since the limestone is fossilliferous it is a pointer that it is coarse and also the diagram above depict that the sediments are fining upward. This simply infer that the limestone(layer A) is the coarsest.
Graded bedding are sediment deposits whereby the coarse rocks are found at the bottom and progressively fine upward. Graded bedding mostly occurs when large amount of sediments are been discharge by a huge force(usually water). It can occur as a discharge of sediment by a landslide underwater, discharge of large sediment by flooding etc. When it occurs in water(landslide) it is most likely it results to graded bedding .
The best explanation for this is that the graded bedding was formed under water in a landslide. The presence of the marine fossils is an evidence the limestone was formed in the sea.