Which of the following processes take place in the cell nucleus?

Answer:
B. DNA replication and DNA transcription
Explanation:
Nucleus is the double membrane bound organelle present in eukaryotic cells. It is the site where DNA is present in these cells.
DNA replication is the process of formation of new DNA strands using the existing ones as a template. It occurs in the nucleus only.
DNA transcription is the process of formation of RNA using a DNA template strand. Since DNA is present in the nucleus only, DNA transcription also occurs in the nucleus.