How Does Atmospheric Fixation Occur Given the High Energy Barrier

How does atmospheric fixation occur given the high energy barrier to convert nitrogen to nitrogen oxides?

A) through the oceans that break the triple bond of nitrogen and allow for the combination with water
B) through clouds that allow for nitrogen to combine with oxygen
C) in the soil by bacteria that reduce nitrogen to ammonia
D) through lightning that breaks the triple bond of nitrogen and allows for the combination with oxygen