Answer:
d. Oxygen causes an arc flash
Step-by-step explanation:
Pure oxygen, even if not a flammable product, when in contact with organic materials (including greases and lubricating oils) causes fire or explosion (confined place) without ignition source; The same goes for contact with certain metals. The cause of this is because it is a highly oxidant product.
The arc flash occurs when there is a dielectric break in which it produces an electrical discharge. This phenomenon is so strong that it can break the insulation made by air by conducting electrons from one electrode to another through a current flow. For the arc flash happens we need to analyze two prime factors: the gas type (which the oxygen is a good candidate) and the pressure at the site.