If you had trouble with this question, check out Pt 58 section 1 q26. Same logic employed, different question type.

i too was hung up on B. but this is such a great explanation.Thanks! I definitely see why B is so wrong. Just because there were carbon deposits at the formation of the earth does not mean petroleum formed at that same moment when there were no living organism. petroleum could have easily formed many many years later when living organisms first emerged.

I was able to load and tried to PT but some questions kept flickering. had to skip as it was impossible to read.