You know what, why we just don't ask someone smart? we can tweet this to someone like that science nigger or someone who knows physics, because its clear everyone here is either retarded or trolling or would never take someone else opinion as a fact.
>>718887072
Read your own answer, the portal is moving but the cube is static, in order to be B the cube would need to win momentum out of nowhere, it would be B if the cube was the one moving at high speed towards the portal not the other way around.