Choose the Item That Best Matches Each Item in the Following

Choose the item that best matches each item in the following:
-A gaseous by-product of anaerobic microbial decomposition

A) peat
B) carbon dioxide
C) mulch
D) crude oil
E) nuclear
F) aerobic
G) coal
H) anaerobic
I) hydrogen fuel cell
J) geothermal
K) natural gas
L) petroleum