Answer:
b. transcriptional control of gene expression.
Explanation:
The binding sites of transcription factors (enhancers and silencers) can activate or deactivate, respectively, a gene in specific parts of the body.
Some genes must be expressed in a part of the body. For example, if you need to activate a gene in the spine, skull and toes, but not in the rest of the body, how can transcription factors do this task?
As a gene of this type of pattern it can have several enhancers or silencers, where each one can activate or repress the gene of a specific type of cell or part of the body, joining transcription factors that occur in that specific part of the body.
