That will be c) the third one
The answer is <span>They decrease</span>
Histone deacetylase is responsible for removing the acetyl group from the histone 3 lysine 9 residue. Remember that deacetylation is one step in converting euchromatin to heterochromatin. Because euchromatin is transcriptionally active (transcriptional machinery is able to reach gene of interest), and blocking histone deacetylase activity would result in an the DNA remaining as euchromatin, we would expect to see an increase in transcriptional activity.
So there’s your answer: An increase in transcriptional activity.
