Question

the energy from fossil fuels is derived from processes that began:
a couple of years ago
tens of years ago
hundreds of years ago
millions of years ago

Explanation:

Fossil fuels form from the remains of ancient organisms that were buried and subjected to heat and pressure over extremely long geological time periods, which spans millions of years. The other time frames are far too short for the complex processes of fossil fuel formation to occur.

Answer:

millions of years ago