ORIGINAL: Red B.
But, what happens if the plane is a tail-dragger and is in the normal three-point attitude, on the runway, in the beginning of the take-off run? The prop-wash obviously cannot go into the runway... so, it deflected, becoming runway-hugging and parallel...
But where does the 'under' prop-wash go now???
It hits the vertical stabilizer and the rudder from the right, causing the plane to veer to the right; the exact opposite to what it does with the plane in level attitude (the 'over' prop-wash will hit nothing, now going over the vertical stabilizer and the rudder...
This 'effect reversal' used to cause beginners in WWII fighters to do the notorious 'ground-loop'... It was usually blamed on 'Torque'...
The would-be pilot would have a bit of trouble explaining what he encountered, from the world he now resides in...
In practice there is no "effect reversal" for full sized warbirds such as the Mustang and the Merlin engined Spitfires. They both need right rudder trim during the take-off sequence (some Spitfire pilots preferred not to use the rudder trim, relying on rudder input only). As the aircraft starts to roll there is a swing towards the left that must be anticipated and corrected for using careful application of right rudder. The tendency to swing towards the left remains during rotation and take off, decreasing quickly as speed increases.