At a pelican crossing, what does a flashing amber light mean?

A flashing amber light at a pelican crossing means that vehicles should give way to any pedestrians who are already crossing the road. Option A is incorrect because accelerating and clearing the crossing could put pedestrians at risk. Option B is incorrect because vehicles are required to give way to pedestrians at a pelican crossing, regardless of a flashing amber light. Option D is incorrect because sounding the horn and proceeding could startle or endanger pedestrians who may not be able to see or hear the vehicle approaching.