>>4632384There are valid arguments in favor of both. The problem is that we have no real theoretical basis for dealing with portals.
If you don't think there are good arguments for option B, then consider the following:
look at this pic. As the portal falls down on top of the block a small amount gets transported to the blue portal, call this dx.
What is the velocity of dx exiting the blue portal? It MUST be equal to the velocity of the orange portal falling.
So the question of this thread is what is the velocity of the block after it exits the blue portal? But if every sliver of the block exiting the portal has a velocity equal to the orange portal falling, then once the block exits the blue portal it will simply adhere to newton's first law, which states that it will continue with its velocity unless acted on by another force, and the only force acting on it is gravity, so it will follow a projectile path.
There are also decent arguments in favor of A, neither one can be completely ruled out without further information on how portals work.