<s>[INST] context: Clinicians recognize three categories of DCS (Decompression Sickness).Mild or type I DCS can include sho-lived mild pains ("niggles"), pruritus, a skin rash, and deep throbbing pain ("bends") resulting from bubbles that form in muscles and joints. Serious or type II DCS can include symptoms in the CNS, lungs, and circulatory system. The CNS disorder--most commonly involving the spinal cord--reflects bubble formation in the myelin sheath of axons that compromises nerve conduction. Symptoms may range from dizziness ("staggers") to paralysis. Pulmonary symptoms ("chokes")--resulting from gas emboli in the pulmonary circulation--include burning pain on inspiration, cough, and respiratory distress. In the circulatory system, bubbles can not only obstruct blood flow but also trigger the coagulation cascade and lead to the release of vasoactive substances. Hypovolemic shock is also a pa of this syndrome. The third category is aerial gas embolization, in which large gas emboli can have catastrophic consequences unless the victim receives immediate recompression treatment. [/INST] question: &;Bends&; are due to | options: A: Escape of nitrogen bubbles from the myelin sheath of motor nerves B: Blockage of pulmonary capillaries by the nitrogen bubbles C: Blockage of blood vessels of brain and spinal cord D: Nitrogen bubbles that form in muscles and joints | answer: D </s>