Answer: Either A or D
Geologists and paleontologists constructed the geologic table based on the relative positions of different strata and fossils, and estimated the time scales based on studying rates of various kinds of weathering, erosion, sedimentation, and lithification.
C=Carbon
O=Oxygen
Oxygen is a diatomic molecule, so the subscript two needs to be used after the O in the formula.
C+O2->CO2
Hope this helps!