**Core Concept**
Call-Exner bodies are characteristic histological features of granulosa cell tumors, a subtype of sex cord-stromal tumors that arise from the ovary. These structures are composed of a central space surrounded by granulosa cells, resembling a rosette or a hobnail pattern under microscopic examination.

**Why the Correct Answer is Right**
The presence of Call-Exner bodies is a diagnostic hallmark of granulosa cell tumors. These structures are formed by the aggregation of granulosa cells around a central space, which may contain fluid or fibrin. The granulosa cells surrounding the Call-Exner bodies exhibit a characteristic hobnail or rosette appearance, with their nuclei pushed towards the periphery. This unique histological feature is a result of the granulosa cells' attempt to surround and encapsulate the central space, which is thought to represent a site of fluid accumulation or cellular degeneration.

**Why Each Wrong Option is Incorrect**
**Option A is incorrect because** the other options listed (embryonal cell carcinoma, choriocarcinoma, and androblastoma) do not characteristically feature Call-Exner bodies in their histological appearance. These tumors have distinct histological features that are not associated with Call-Exner bodies.

**Option B is incorrect because** embryonal cell carcinoma is a type of germ cell tumor that typically exhibits a primitive, undifferentiated appearance under the microscope, with features such as large cells with prominent nucleoli and a high mitotic rate.

**Option C is incorrect because** choriocarcinoma is a type of trophoblastic tumor that is characterized by the presence of cytotrophoblasts and syncytiotrophoblasts, with a distinctive "placental" or "mural" type of histological appearance.

**Option D is incorrect because** androblastoma, also known as Sertoli-Leydig cell tumor, is a rare sex cord-stromal tumor that typically exhibits a distinctive "Sertoli cell" or "Leydig cell" type of histological appearance, with features such as tubules or cords of cells.

**Clinical Pearl / High-Yield Fact**
It is essential to recognize the histological features of granulosa cell tumors, including the presence of Call-Exner bodies, as this can aid in the diagnosis and differentiation of these tumors from other ovarian neoplasms. A high index of suspicion and careful examination of histological sections are crucial in identifying these characteristic features.

**✓ Correct Answer: A. Granulosa Cell Tumour**