B) Unless your method of contacting the armor does not involve magic, the armor cannot be summoned.
However, if the trigger is say, spinning around like sailor moon and shouting, "By The Power of Greyskull!" and the armor was close enough to hear the trigger phrase, then the armor would teleport. However, anti-magic areas block teleportation. So the armor appears in the closest unoccupied square and falls to the ground.
Unless of course you have armor summoning as an extraordinary ability, in which case it works in antimagic zones.
Or, depending on your campaign, Artifacts work in antimagic zones, so if you have artifact armor, it'd work.