**Core Concept**
HCG (human chorionic gonadotropin) is a hormone produced by the placenta during pregnancy, playing a crucial role in maintaining the corpus luteum and supporting embryonic development. Its levels in maternal blood and urine are used as markers for pregnancy confirmation and dating.

**Why the Correct Answer is Right**
HCG levels typically peak in the first trimester, around 8-11 weeks of gestation. This surge is due to the rapid growth of the placenta and the increased production of HCG by the syncytiotrophoblast cells. The maximum urinary HCG level is reached when the embryonic implantation is confirmed, and the placenta starts to mature. This timing is essential for early pregnancy dating and monitoring.

**Why Each Wrong Option is Incorrect**
**Option A:** This would be too early, as HCG levels start to rise after implantation, but there's a delay before reaching the peak.
**Option B:** This would be too late, as HCG levels start to decline after the first trimester, marking the beginning of the second trimester.
**Option C:** This is not a valid option, as the correct answer is not provided.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that HCG levels are used to estimate gestational age, with a doubling time of approximately 48 hours in the first trimester. This helps in early pregnancy dating and monitoring.

**Correct Answer: C. 8-11 weeks.**