What is the site of transcription in a cell?

The site of transcription in a cell is the nucleus. Transcription is the process where DNA is used as a template to synthesize messenger RNA (mRNA). This process occurs in the nucleus because it is where the cell's genetic material (DNA) is housed.

During transcription, RNA polymerase binds to a specific region of the DNA, unwinding the double helix and synthesizing a complementary strand of RNA. Once synthesis is complete, the mRNA molecule exits the nucleus and enters the cytoplasm, where it will be translated into a protein by ribosomes.

The other options represent different cellular structures and functions. Ribosomes are crucial for translation, the process that reads mRNA to synthesize proteins, while the cytoplasm is the site of many cellular metabolic activities but not transcription. The Golgi apparatus is involved in modifying, sorting, and packaging proteins and lipids but does not play a role in the process of transcription. Therefore, the nucleus is indeed the correct and exclusive site of transcription in eukaryotic cells.