If you examine a rock sample and observe fossils in it what type of rock does the sample represent?

Fossils are only found in rocks that are laid down on the surface of the Earth. The majority of fossiliferous rocks are therefore sedimentary BUT fossils are also occasionally found in lava flows (igneous rocks) - eg lava trees and in some metamorphosed sedimentary rocks (metamorphic rocks) - eg the "delabole butterfly"