**Core Concept**
Deep vein thrombosis (DVT) is a condition characterized by the formation of a blood clot in the deep veins, typically in the legs. This condition can lead to various symptoms and signs due to venous obstruction and subsequent inflammation.

**Why the Correct Answer is Right**
Claudicatio intermittentia, or intermittent claudication, is a symptom typically associated with arterial insufficiency, particularly in the context of peripheral artery disease (PAD). It is characterized by pain in the muscles of the lower extremities during exercise, which is relieved by rest. In contrast, DVT is associated with venous obstruction, leading to symptoms such as pain, swelling, and discoloration (e.g., erythema and ecchymosis) due to venous congestion and inflammation. The lack of arterial blood flow in claudication is distinct from the venous obstruction seen in DVT.

**Why Each Wrong Option is Incorrect**
**Option A:** Pain is a common symptom of DVT, often described as a dull, aching, or cramping sensation in the affected limb. This pain can be exacerbated by movement and relieved by rest.
**Option B:** Discolouration, including erythema and ecchymosis, is a characteristic sign of DVT due to venous congestion and inflammation.
**Option C:** Swelling is another common symptom of DVT, resulting from venous obstruction and subsequent fluid accumulation in the affected limb.

**Clinical Pearl / High-Yield Fact**
It is essential to note that DVT can be asymptomatic in up to 50% of cases, emphasizing the importance of vigilant clinical evaluation and diagnostic testing in patients at risk.

**✓ Correct Answer: D. Claudication**