What position will have the smallest magnitude of vertical velocity?

-- The magnitude of acceleration is the same at all the positions. 
It's 9.8 meters per second-squared downward if this is all happening
on Earth.

-- The smallest magnitude of vertical velocity has to be at the top ... point-B.
In order to change from moving up to moving down, there has to be an instant
when the vertical velocity is zero, and it can't get any smaller than that.

Iwould sure like to answer your question but i honestly just don’t know

So are u adding some additional catalyst