**Core Concept**
Familial Retinoblastomas are a type of cancer that affects the retina of the eye, characterized by the uncontrolled growth of cells. The inheritance pattern of familial Retinoblastomas is a classic example of an autosomal dominant genetic disorder, where a mutation in one copy of the RB1 gene is sufficient to cause the condition.

**Why the Correct Answer is Right**
The RB1 gene encodes for the retinoblastoma protein, which regulates the cell cycle by inhibiting cell proliferation. A mutation in the RB1 gene leads to the loss of this regulatory function, resulting in uncontrolled cell growth and tumor formation. The autosomal dominant inheritance pattern means that a single copy of the mutated gene is sufficient to cause the condition, and each offspring of an affected individual has a 50% chance of inheriting the mutated gene.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because familial Retinoblastomas do not follow an autosomal recessive inheritance pattern, where two copies of the mutated gene (one from each parent) are required to cause the condition.
* **Option B:** This option is incorrect because familial Retinoblastomas are not typically associated with an X-linked inheritance pattern, where the mutated gene is located on the X chromosome and affects males more frequently than females.
* **Option C:** This option is incorrect because familial Retinoblastomas are not typically associated with a multifactorial inheritance pattern, where multiple genetic and environmental factors contribute to the development of the condition.

**Clinical Pearl / High-Yield Fact**
The RB1 gene is a tumor suppressor gene, and mutations in this gene are not only associated with Retinoblastomas but also with other types of cancers, such as osteosarcoma and soft tissue sarcomas.

**Correct Answer: D. Autosomal Dominant**