The correct answer is "B" - using your rifle bayonet. A rifle with bayonet mounted can extend to over 1.7 metres. This gives it the length to stab down at defenders in a trench, or to defend against a enemy's bayonet thrust.

Firing your rifle at close range is dangerous and not effective. It can get jostled or pushed away, and possibly shoot one of your own men.

Grenades are not standard issue. Some soldiers at the front have tried making their own using jam tins, nails and explosives but these are not reliable and could explode prematurely among your own men.

Using clubs, knives or shovels are weapons is simply barbaric. It is not how civilized men fight.