Final answer:
Vitamin K enhances blood clotting by activating clotting factors that are necessary for the formation of a stable clot.
Step-by-step explanation:
The option that enhances blood clotting is Vitamin K. Vitamin K plays a crucial role in the coagulation process by activating several clotting factors produced by the liver. These clotting factors help convert fibrinogen into fibrin, which is essential for forming a stable clot. Therefore, a deficiency in Vitamin K can lead to issues with blood clotting.
It should be noted that options such as aspirin and smoking are known to impair clotting -- aspirin by inhibiting platelet function and smoking by damaging the endothelium and altering the balance of coagulative factors. A low red blood cell count does not directly influence clotting but can have overarching effects on general health, including oxygen transport capacity.