Final answer:
A tourniquet band made from a Muslim bandage should be at least 4 centimeters wide when folded, used as a last resort in bleeding emergencies.
Step-by-step explanation:
When applying a tourniquet band using a Muslim bandage, the improvised band should be wide enough to stop blood flow without cutting into the skin. A good rule of thumb is to use a tourniquet band that is at least 4 centimeters (about 1.5 inches) wide when folded. It's important to note that while an improvised tourniquet can be life-saving in a bleeding emergency, it should only be used when direct pressure to a wound is ineffective or impossible, and as a last resort.