**Core Concept**
Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome is a congenital disorder characterized by the underdevelopment or absence of the uterus and vagina. This condition is often associated with other anatomical anomalies, such as renal and skeletal abnormalities.

**Why the Correct Answer is Right**
The primary feature of MRKH syndrome is the failure of Müllerian duct development, which is essential for the formation of the female reproductive tract. Normally, the Müllerian ducts fuse and develop into the uterus, cervix, and upper part of the vagina. In MRKH syndrome, the Müllerian ducts fail to develop, resulting in the characteristic absence or underdevelopment of the uterus and vagina. This condition is often diagnosed during puberty when secondary sexual characteristics begin to develop, but menstruation does not occur.

**Why Each Wrong Option is Incorrect**
* **Option A:** MRKH syndrome is not characterized by the presence of a rudimentary uterus, which is a feature of other Müllerian duct anomalies such as Mayer-Rokitansky-Küster-Hauser variant with a rudimentary uterine horn.
* **Option B:** MRKH syndrome is not primarily associated with a uterine agenesis, which is a condition where the uterus is completely absent but the vagina is normal.
* **Option C:** MRKH syndrome is not a condition of androgen insensitivity, which is a genetic disorder that affects the development of male external genitalia.
* **Option D:** MRKH syndrome is not characterized by the presence of testes, which is a feature of androgen insensitivity syndrome.

**Clinical Pearl / High-Yield Fact**
MRKH syndrome often co-exists with other congenital anomalies, such as renal and skeletal abnormalities, which should be carefully evaluated during the diagnostic workup.

**Correct Answer:** C.