What Do the Components of a Liquid O₂ Bulk Storage

What do the components of a liquid O₂ bulk storage tank include?
1) Inner and outer steel shells, separated by a vacuum
2) Safety system that vents O₂ if warming occurs
3) Vaporizer system that converts liquid O₂ to gas
4) Pressure-reducing valves to lower pressure to 50 psig

A) 1, 2, and 3 only
B) 2 and 4 only
C) 1, 2, 3, and 4
D) 3 and 4 only