**Core Concept**
Small sized platelets on the peripheral smear are indicative of a condition affecting platelet production, with the most common cause being a disorder of megakaryopoiesis. This involves a defect in the maturation of megakaryocytes, leading to the release of abnormally small platelets into the circulation.

**Why the Correct Answer is Right**
The correct condition associated with small sized platelets is Thrombocytopenia with normal megakaryocyte number (also known as Isolated Thrombocytopenia or Pseudothrombocytopenia). In this condition, the small platelets are a result of the release of platelet fragments from damaged megakaryocytes, rather than a true reduction in platelet production. The pathophysiology involves the abnormal function of the megakaryocytes, leading to the release of small, immature platelets into the circulation.

**Why Each Wrong Option is Incorrect**
**Option A:** Bernard-Soulier syndrome is characterized by large platelets, not small ones, due to a defect in the GPIb-IX-V complex.
**Option B:** Idiopathic thrombocytopenic purpura (ITP) is characterized by large platelets due to the increased turnover of platelets, but not small sized platelets.
**Option C:** Thrombocytopenia with normal megakaryocyte number is not the same as thrombocytopenia with decreased megakaryocyte number, which would also be associated with small sized platelets due to the reduced production of platelets.

**Clinical Pearl / High-Yield Fact**
It's essential to distinguish between conditions causing small sized platelets, such as Thrombocytopenia with normal megakaryocyte number, and those causing large platelets, such as Bernard-Soulier syndrome or ITP, as the management and prognosis of these conditions differ significantly.

**Correct Answer:** C.