Answer is d) none of these.
Fossils are the physical remains or traces of the past life which were preserved in the rock. Fossils are the direct evidence of past life and the process by which parts of a living thing are buried and preserved as fossils is called Taphonomy.
There are two types of major fossils. These are trace fossils such as footprints, burrows, nests, fossilized feces and body fossils such as such as teeth, bones, shells, wood, leaves, pollen, etc.