(me d: i've been trying to figure this out all day)

OK.  Relax, settle down, don't worry.

We're in luck here.  The shape hasn't been rotated, or swelled up
or shrunk.  It's still exactly the same size and shape, and in the same
position.  It's only been moved, from here to there.  All you really
have to do is look at one point, and figure out how that point moved,
and all the other points moved exactly the same ... same distance,
in the same direction.

When I looked at this, I worked with point-D.  But now I think
point-B may be a little easier to work with.

-- What's the 'x'-value (left/right) of point-B before it moves ?
    It's right on the y-axis, so its x-value is zero.

-- What's the 'x' value of point-B', after the move ?
    Look at the light light line that B' is on, follow it down,
    and you see that the x-value of point-B' is  6 .

-- The x-value of point-B moved from  x=0  to  x=6.
    If you look at just the x-value of any other point on the shape,
    you'll see that every point moved 6 units to the right.
    Every 'x'-value became 6 units bigger after the move.
       x --> x+6


 
-- What's the 'y'-value (up/down) of point-B before it moves ?
    It's in the middle between the 2 and the 4, so its y-value is 3.

-- What's the 'y' value of point-B', after the move ?
    Look at the light light line that B' is sitting on, follow it left,
    and you see that the y-value of point-B' is  8 .

-- The y-value of point-B moved from  y=3  to  y=8.
    If you look at just the y-value of any other point on the shape,
    you'll see that every point moved 5 units UP.
    Every 'y'-value became 5 units bigger after the move.
       y --> y+5

Look for a choice that says what we found.
The second choice says it.

Distance=slopeslope is -2/4which equals-1/2the distance between these two points is -1/2