Specialization unlock questions

first question: once you have gone through an entire specialization do you get to keep the Armor, weapon skin, and armor mod when you go to another specialization?

if you dont get to keep the stuff, can you go back to a specialization you previouslly completed?

second question: Do you have to use the armor that the specialization has, or can you just use whatever armor you want.

a) You keep all the stuff.

b) You keep it.

C) And no, the Armor Mod you get can be used in ANY armor combination. It’s equipped in a Loadout.