**Core Concept**
A complete mole is a type of gestational trophoblastic disease (GTD) characterized by the abnormal proliferation of trophoblastic cells in the placenta, leading to the formation of a hydropic placenta. The karyotype of a complete mole is primarily diploid, but it is derived from a single parental set of chromosomes.

**Why the Correct Answer is Right**
The karyotype of a complete mole is typically 46,XX (or 46,XY in rare cases) because it is derived from an empty follicle in the ovary that is fertilized by a single sperm, resulting in a complete duplication of the paternal genome. This is in contrast to a partial mole, which has a triploid karyotype (69,XXX, 69,XXY, or 69,XYY). The formation of a complete mole is often associated with hyperplasia of the cytotrophoblast and an absence of fetal development.

**Why Each Wrong Option is Incorrect**
* **Option A:** A triploid karyotype is characteristic of a partial mole, not a complete mole.
* **Option B:** A tetraploid karyotype is not a typical characteristic of a complete mole.
* **Option D:** A complete mole is not typically associated with a biparental origin of the chromosomes.

**Clinical Pearl / High-Yield Fact**
A complete mole is often associated with hyperemesis gravidarum, uterine bleeding, and a high risk of developing gestational trophoblastic neoplasia (GTN).

**Correct Answer:** C. 46,XX.