**Core Concept**
Warthin-Finkeldey cells are a type of giant cell seen in the lymphoid tissues, particularly in the context of viral infections. These cells are characterized by the presence of multiple nuclei and are often associated with congenital infections such as cytomegalovirus (CMV) and rubella.

**Why the Correct Answer is Right**
Warthin-Finkeldey cells are typically seen in the lymphoid tissues, including the lymph nodes and spleen, in response to congenital viral infections. The presence of these cells is a indicator of a viral infection, particularly CMV and rubella, which can cause significant morbidity and mortality in neonates. The cells are thought to be a result of the fusion of infected cells and the subsequent proliferation of the infected cells.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Warthin-Finkeldey cells are not typically associated with autoimmune disorders or other non-infectious conditions.
**Option B:** This option is incorrect because while giant cells can be seen in various conditions, Warthin-Finkeldey cells are specifically associated with congenital viral infections.
**Option C:** This option is incorrect because while lymphoid tissues are the primary site of Warthin-Finkeldey cells, they are not typically seen in the context of malignancy.

**Clinical Pearl / High-Yield Fact**
Warthin-Finkeldey cells are a classic example of a congenital viral infection and should be considered in the differential diagnosis of lymphadenopathy in neonates.

**Correct Answer: C. Lymphoid tissues.**