In order to test the effects of a new drug, you isolate the messenger RNA molecules from both treated and untreated eukaryotic cells and separate them according to size using gel electrophoresis. In each lane of the gel, the shorter RNA molecules migrate more quickly through the gel and end up near the bottom of the gel while the longer RNAs migrate more slowly and remain near the top. The samples that were loaded into each of the four lanes are as follows:

Lane 1: the primary RNA transcripts isolated from the nucleus of untreated cells
Lane 2: the primary RNA transcripts isolated from the nucleus of cells treated with the drug being tested
Lane 3: RNA isolated from the cytosol of untreated cells
Lane 4: RNA isolated from the cytosol of cells treated with the drug being tested

Which of the following conclusions is most likely to be CORRECT?

A. These results suggest that the drug affects RNA processing.
B. These results suggest that the drug digests DNA.
C. These results suggest that the drug inhibits DNA replication.
D. These results suggest that the drug contains a protease that targets this gene product.
E. These results suggest that the drug inhibits post-translational processing of this gene.