Answer:
c. Historically low prices for oil
Explanation:
There are countless reasons as to why the world has been looking for other non-conventional fossil fuels but historically low prices for oil have not helped this endeavor. This is because lower prices causes increased demand for oil. Therefore, more people simply buy oil instead of looking for and purchasing other fuel solutions. Without this demand/interest for other fuels the progress is halted or at least staggered. On the other hand, higher global energy demand and depletion of oil reserves is what pushes the need to find non-conventional fossil fuels, while improved technology facilitates the extraction process of these fuels.
