Final answer:
DNA methylation is a form of epigenetic regulation affecting gene expression by modifying DNA to influence transcription, typically leading to decreased gene expression. It is not involved in post-translational regulation. Therefore, the correct answer to the question is: A. DNA methylation is a form of transcriptional regulation of gene expression.
Step-by-step explanation:
DNA methylation is a form of epigenetic regulation of gene expression. This process involves the modification of DNA molecules or associated histones, which influences transcription. When cytosine nucleotides in DNA are methylated, this commonly correlates to lowered levels of gene expression.
DNA methylation can be influenced by environmental factors and these changes can sometimes be heritable as they may persist through multiple rounds of cell division.
Post-translational control, on the other hand, refers to the regulation of gene expression that occurs after a protein has been made. Thus, DNA methylation does not fall under the category of post-translational regulation.
Therefore, the correct answer to the question is: A. DNA methylation is a form of transcriptional regulation of gene expression.