Final answer:
The correct answer is A) start, promoter region. The TAC sequence is the start of a gene's coding region and is immediately preceded by the promoter region, which is essential for initiating transcription.
Step-by-step explanation:
The TAC sequence of DNA is the start of a coding sequence that is preceded by the promoter region that regulates transcription. Thus, the answer to this question is A) start, promoter region. In biology, particularly in genetics and molecular biology, the promoter region of DNA includes sequences like the TATA box, which is crucial for the binding of transcription factors and RNA polymerase to initiate the process of transcription. This sequence is found upstream (toward the 5' direction) of the transcriptional start site of a gene. The TATA box, a part of the promoter, is an adenine-thymine-rich sequence that facilitates the unwinding of the DNA template, allowing transcription to begin at the correct location.