The 300 tonner as lift =weight, and induced drag is proportional to the square of lift.
And because 'landing' flap, as opposed to 'takeoff' flap, will reduce the AoA of the outer wing sections, and thereby also, the
intensity of the wingtip vortices.
At the same time, new vortices are created at the edges of the flaps, thus spreading the total energy of the trailing vortices across the wingspan, rather than having it concentrated at the wingtips.
I suspect that, If it were possible to add up the energy of all the trailing vortices in the landing configuration, it would be greater than the the 'clean', or 'takeoff' case.
Perhaps the question should read:
What generates most
hazardous wake vortex;
MJ
