Enzyme responsible for breaking down of the N ≡ N

Answer: Option A

Nitrogenase is the enzyme responsible for breaking down the N ≡ N bonds.
It is the enzyme produced by cyanobacteria and rhizobacteria and is responsible for the reduction of nitrogen to ammonia. Nitrogenases are the only family of enzymes known to catalyze this reaction, which is the key step in the process of nitrogen fixation.