**Core Concept**
Human chorionic gonadotropin (hCG) is a glycoprotein hormone produced by the placenta during pregnancy. It plays a crucial role in maintaining the corpus luteum, which produces progesterone, essential for embryonic development.

**Why the Correct Answer is Right**
hCG levels reach a peak in maternal serum around 10 weeks of gestation. This surge in hCG helps to maintain the corpus luteum, ensuring continued progesterone production. The hCG peak is crucial for embryonic implantation and fetal development.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because hCG levels do not peak at 6-8 weeks of gestation, although they do start to rise significantly around this time.
* **Option B:** This option is incorrect because hCG levels do not reach a peak after 12 weeks of gestation, although they may remain elevated throughout pregnancy.
* **Option C:** This option is incorrect because hCG levels do not peak at 14-16 weeks of gestation, which is closer to the time when the first-trimester screening for Down syndrome is performed.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that hCG levels can be affected by various factors, including multiple gestations, molar pregnancies, and certain medical conditions. Abnormal hCG levels can have significant implications for maternal and fetal health.

**Correct Answer:** C. 10 weeks of gestation.