From my
understanding induced drag is highest when at high weights and at low speed
clean configuration. - more time for the vortices to develop
The answer given is VSO (Landing configuration)
when in the landing configuration with gear down - more profile drag and flaps
will be down too with the centre of lift moving inwards form the wing tips...
You are
correct in your reasoning but VSO is the stalling speed in the landing
configuration, and that is substantially slower than the other 3 options. The
lower speed more than compensates for the reduction in the flow around the tips
from the other factors.