The statement probably talks about a situation in which a boy catches fire and the neighbour saves him. The neighbour did that by grabbing and then rolling him on the road to extinguish the fire. We have to pick the right word that describes this action. Option (b) is correct, because to kill the flames would mean extinguishing the fire and this is exactly what is needed here. Option (a) is wrong. Option (c) is wrong, because the flames do not burn out, the fuel does. Option (d) is wrong, because fizz refers to become bubbly or frothy, so it is clearly not the right word here.