**Core Concept**
Dengue haemorrhagic fever (DHF) is a severe form of dengue infection characterized by **thrombocytopenia**, **hemorrhagic manifestations**, and **plasma leakage**. The disease severity is graded based on clinical and laboratory criteria.

**Why the Correct Answer is Right**
The patient's symptoms, including **myalgia** and **spontaneous skin bleeds**, along with lab findings of **thrombocytopenia** and a **raised hematocrit**, indicate significant plasma leakage and hemorrhage. These features are consistent with a more severe form of the disease.

**Why Each Wrong Option is Incorrect**
**Option A:** This option would represent a milder form of the disease, not consistent with the patient's severe symptoms.
**Option B:** While closer, it still doesn't fully capture the severity indicated by the combination of thrombocytopenia, hemorrhage, and plasma leakage suggested by the raised hematocrit.
**Option D:** This would be an even more severe form, potentially with more profound shock, which is not indicated in the scenario provided.

**Clinical Pearl / High-Yield Fact**
DHF grading is crucial for management and prognosis. Recognizing the severity based on clinical and lab findings like thrombocytopenia and hematocrit levels is key.

**Correct Answer:** D. Grade III DHF is not indicated, the description best fits **Grade II** with spontaneous bleeding and low platelets but no mention of circulatory failure or severe shock, so: **Correct Answer: C. Grade II**