>>509269298
The answer is obviously A. The portals are not objects or doorways, they're teleporters. B makes the assumption that the portals are 2 sides of a door and that the momentum of one side is conserved in the "reference frame" of the other. If B were true then by moving the orange portal you'd be accelerating the entire universe of the blue portal. The second the orange portal starts to accelerate you would feel a change in gravity. This is not the case. They're just teleporters that conserve the momentum of anything that touches them. Now here's the real question... what do when nested portals?