You’re both wrong, but you’re half right. I don’t understand how the ancient forest guy got the upvotes, because he’s completely wrong.

Phytoplankton are microscopic plants that, just like plants that live on land, require access to the sun to survive through the process of photosynthesis (turning sunlight into energy using chlorophyll).

Zooplankton are microscopic animals that feed upon phytoplankton to survive.

These tiny creatures do not have very long lifespans (a few weeks at most), so they are reproducing and dying at a very rapid rate. When these microscopic creatures die, they sink to the floor of the ocean.

Over time, the plankton are buried and mixed underneath layers of sand, silt, and rock. This process has occurred since these creatures evolved over 1 billion years ago and continues to this day…

https://bkvenergy.com/learning-center/where-does-oil-come-from/