What is the number of Barr bodies seen in cells of person with Klinefelter syndrome?

**Core Concept**
Klinefelter syndrome is a genetic condition characterized by an extra X chromosome in males, resulting in 47,XXY karyotype. This condition leads to the formation of Barr bodies, which are inactivated X chromosomes. The number of Barr bodies in a cell is directly related to the number of X chromosomes.

**Why the Correct Answer is Right**
In individuals with Klinefelter syndrome, the extra X chromosome is inactivated to form a Barr body. This means that in each cell, there will be one Barr body, corresponding to the extra X chromosome. The presence of a Barr body is a hallmark of Klinefelter syndrome and can be used for diagnostic purposes.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because individuals with Klinefelter syndrome have one extra X chromosome, not two, which would result in two Barr bodies per cell.
**Option B:** This option is incorrect because it does not account for the inactivation of the extra X chromosome, which forms a Barr body.
**Option C:** This option is incorrect because it suggests that individuals with Klinefelter syndrome have a normal number of Barr bodies, which is not the case.

**Clinical Pearl / High-Yield Fact**
A key feature of Klinefelter syndrome is the presence of one Barr body per cell, which is a result of the inactivation of the extra X chromosome. This can be used as a diagnostic clue in individuals with a 47,XXY karyotype.

**Correct Answer:** C. 1