Choice-C is the closest to being a description of velocity,
but I also have problems with ‘C’. 

In order to describe velocity, you need a speed and its direction.

‘A’ doesn’t state either one.

‘B’ says “quickly”, which I don’t accept as a speed, and “down the court”,
which I don’t accept as a direction. 

‘D’ nicely describes the speed … 120 kph.  But the only thing it
tells us about direction is that it must have changed during the
race, because that’s the only way the driver could have ended
the race in the same place she started it from.

‘C’ gives us the skier’s speed … (80 meters) / (3.5 sec)  =  22.86 m/s .
It also tells us that his direction was always downhill and along the track.
I would have preferred a better description of the direction, but I can
have it if I’m willing to go there and measure the direction of the track
and the slope of the hill.  So it’s all there in this choice, but you have to
dig for it.