As has been said, anything that demands a higher angle of attack to generate lift will increase wake turbulence, as that is essentially where it comes from.
Flying fast, adding flap (increasing wing camber and possibly increasing wing surface area) and being light all assist with lift (or reduce the need for it) and allow for a lower AoA which therefore reduces wake turbulence.
Light winds are normally cited as the worst scenario as the wake vortices can drift back onto the centreline (as opposed to dissipating left and right in calm conditions or being 'destroyed' by strong winds).
The given answer seems correct enough to me.