**Core Concept**
Trisomies are chromosomal disorders characterized by the presence of an extra chromosome, leading to genetic imbalances. In human genetics, trisomies can occur due to non-disjunction during meiosis or mitosis, resulting in an abnormal number of chromosomes.

**Why the Correct Answer is Right**
Trisomy 16 is the most common trisomy in humans, occurring in approximately 1 in every 100 conceptions. It is estimated that nearly 50% of all miscarriages are due to trisomy 16. This is because trisomy 16 is often incompatible with fetal development, leading to spontaneous abortion. The presence of trisomy 16 is usually not detectable through routine ultrasound or maternal serum screening, making it difficult to diagnose prenatally.

**Why Each Wrong Option is Incorrect**
**Option A:** Trisomy 21, also known as Down syndrome, is a well-known condition characterized by intellectual disability and physical abnormalities. However, it is not the most common trisomy.

**Option B:** Trisomy 18, also known as Edwards syndrome, is a severe chromosomal disorder associated with multiple congenital anomalies and a high mortality rate. It is less common than trisomy 16.

**Option D:** Trisomy 13, also known as Patau syndrome, is a rare chromosomal disorder characterized by severe intellectual disability and physical abnormalities. It is even less common than trisomy 18.

**Clinical Pearl / High-Yield Fact**
Prenatal diagnosis of trisomies can be challenging, and many cases are diagnosed postnatally or through miscarriage analysis. However, advances in genetic testing and non-invasive prenatal testing (NIPT) have improved the detection of trisomies, including trisomy 16.

**✓ Correct Answer: C. Trisomy 16**