Answer:(B) DENITRIFICATION
Explanation: Denitrification is the process through which Facultative anaerobic Bacteria reduces Nitrite ions into Nitrogen gas,this bacteria facilitates this process through respiration.
This process is one of the major causes of Global warming through the release of Green house gas called DENITROGEN-OXYDE into the atmosphere. Most of the Facultative anaerobic Bacteria are of the Pseudomonads and Paracoccus species.