The correct option is B the number of military personnel it takes to supply and support each combat soldier.
The tooth-to-tail ratio is a military term that refers to the amount of military personnel ("tail") it takes to supply and support each combat soldier ("tooth"). While both "tooth" and "tail" soldiers may find themselves in combat or other life-threatening situations "tooth" soldiers are those whose primary function is to neutralize the enemy. The ratio is not a specific measure but rather a general indication of an army's actual military might in relation to the resources it devotes to supply, upkeep, and logistics. In short:” The tooth-to-tail ratio, referred to as T3R in the Army, is the ratio of fighting arms, which wage the actual battle such as infantry and armoured wings, to support services, such as logistics, signals and ordnance.”