The best answer is B.
Though the Zulus had some success in driving back the British in the very first stages, the superior weapons and horses of their enemies eventually led to the rapid defeat of the Zulu.
The British forces not only possessed cavalry and artillery, but they had also been equipped with the newest and finest weapon for infantry soldiers at the time. This weapon was the Martini Henry .45 caliber breach loading rifle.
This coupled with cavalry enabled the British not only to have superior destruction ability, but also could deploy much more rapidly than the Zulus who fought on foot.