The correct answer is: a) Flaking.
Flaking is the process of removing small pieces of stone from a larger piece to create a tool. It is the oldest known toolmaking technique and was used by early humans to create a variety of tools, including axes, knives, and scrapers.
Grinding is the process of shaping a stone by rubbing it against another stone or a hard surface. It is a more advanced toolmaking technique than flaking and was used to create more complex tools, such as axes and adzes.
Polishing is the process of smoothing and shining a stone by rubbing it against another stone or a hard surface. It is the most advanced toolmaking technique and was used to create tools that were both functional and aesthetically pleasing.
Drilling is the process of making a hole in a stone by rotating a sharp tool against it. It is a relatively advanced toolmaking technique that was not used until the Neolithic period.
Flaking is the most likely answer to the question because it is the oldest known toolmaking technique and was used by early humans to create a variety of tools.