This has been really heavily debated before and the unanimous answer is B IRL and A for portal.

How does the cube move out of the blue portal? If you ignore the orangep portal entirely and consider just looking from the side as the cube emerges from the blue portal, the top has to be moving extremely fast. The cube needs to be moving relative to the blue portal at the same speed as the orange portal is descending or it doesn't work.

You can also draw a force balance diagram and you get the same result...

But you're welcome to disagree with me! That's part of the wonder of the internet.