Answer:
Option (A) and (C).
Explanation:
Gene regulatory mechanism are important for the regulation of the transcription and proper expression of genes. Different regulatory mechanisms are present in prokaryotes and eukaryotes.
The prokaryotes do not require the multiple general transcription factors where as the eukaryotes have different transcription factors like TFIID, TFIIH and TFIIA. The DNA is packed around the histone protein that form chromatin in eukaryotes. The chromatin packaging includes methylation, ribosylation with the help of enhancers and silencors. The chromatin is absent in case of prokaryotes.
Thus, the correct answer is Option (A) and (C).