**Core Concept**
Sarcoma botyroides, also known as embryonal rhabdomyosarcoma, is a rare type of cancer that primarily affects the genitourinary system, particularly in infants and young children. It is characterized by its distinctive "botryoid" or grape-like appearance under microscopic examination.

**Why the Correct Answer is Right**
Sarcoma botyroides typically presents in the vagina or bladder of infants and young children, with a peak incidence between 6 months and 2 years of age. This age group is particularly susceptible to this type of cancer due to the presence of embryonal cells that are more prone to malignant transformation. The tumor's botryoid appearance is due to the presence of embryonal rhabdomyoblasts, which are immature muscle cells that have not yet differentiated into mature muscle fibers.

**Why Each Wrong Option is Incorrect**
**Option A:** This age range is incorrect because sarcoma botyroides typically presents in infants and young children, not in adults or older children.
**Option B:** This option is incorrect because while sarcoma botyroides can occur in the vagina, it is not exclusive to this location and can also occur in other parts of the genitourinary system.
**Option C:** This option is incorrect because while sarcoma botyroides is a rare type of cancer, it is not the most common type of cancer in infants and young children.

**Clinical Pearl / High-Yield Fact**
Sarcoma botyroides is often referred to as the "most common soft tissue sarcoma in children" and is characterized by its rapid growth and potential for metastasis, making prompt diagnosis and treatment essential.

**Correct Answer: D. 6 months to 2 years.**