**Core Concept**
A transverse vaginal septum is a congenital anomaly characterized by a complete or partial obstruction of the vaginal lumen due to a thin membrane of tissue that separates the vagina into two compartments. This condition can present with symptoms such as pelvic pain, vaginal bleeding, and difficulty with menstrual flow.

**Why the Correct Answer is Right**
A transverse vaginal septum is typically located in the mid-vagina, and its exact location can vary. The septum can be composed of fibrous tissue, muscle, or a combination of both. The presence of a transverse vaginal septum can lead to hematocolpos (accumulation of menstrual blood in the vagina) and hematometra (accumulation of menstrual blood in the uterus).

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because a transverse vaginal septum is indeed a congenital anomaly, and its presentation can vary from asymptomatic to severe pelvic pain and difficulty with menstrual flow.
**Option B:** This option is incorrect because a transverse vaginal septum can be composed of fibrous tissue, muscle, or a combination of both, not just fibrous tissue.
**Option C:** This option is incorrect because a transverse vaginal septum can present with symptoms such as pelvic pain, vaginal bleeding, and difficulty with menstrual flow, not just one symptom.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that a transverse vaginal septum can be diagnosed using imaging studies such as ultrasound and MRI, and treatment may involve surgical resection of the septum to restore normal vaginal anatomy.

**Correct Answer:** A.