Hi Nicole,
The text for Experiment 2 indicates that 5aza is a demethylating drug.
As for the increased expression, this was derived from the question stem and information from Experiment 2 passage. It states that 5aza is a demethylase, so it decreases methylation.
From the stem, we are told that increased demethylation decreases expression, so in other words, decreased methylation, decreases expression. So, it would stand that D would be the correct answer.
Hope that helps, and happy studying!
Cheers,
Molly