C - An RLW is only applied when performance is affected (short runway, wet runway etc.)and MEL/CDL items. So C is a no.
A - Unilaterally changing the figures on the loadsheet to refect what you think may happen (whether based on experience or not)is not a good idea either as the figures on the loadsheet and the flight plan must match.
So A is not an option either.
That leaves B without abitrarily changing the MLW.