Passage Ethanol Is an Important Source of Energy That Is Frequently

Passage
Ethanol is an important source of energy that is frequently used as a supplement to gasoline.  It can be obtained from renewable resources such as the cellulose found in plant matter.  When subjected to a process called gasification, the plant mass is converted to a mixture called syngas, composed predominantly of carbon monoxide and molecular hydrogen.  Syngas can be passed over a rhodium catalyst to generate ethanol and other products.  After using this method, a group of researchers analyzed the resulting products by gas chromatography using helium as a carrier gas.  The results are shown in Figure 1.
Figure 1  Gas chromatograph of syngas catalysis productsMass spectrometry revealed that the process yielded similar amounts of ethanol, acetic acid, and acetaldehyde, with trace amounts of ethane.  In addition, the ethanol peak was found to be contaminated with ethyl acetate.  Another group of researchers in the same laboratory had recently produced Compound 1 as a by-product in a separate reaction.  They combined Compound 1 with purified ethyl acetate to form megestrol acetate, a drug used in the treatment of certain cancers.  This reaction also produced ethanol, as shown in Scheme 1.
Scheme 1
Adapted from Lopez L, Velasco J, Montes V, Marinas A, Cabrera S, Boutonnet M, Järås S. Catalysts  2015.
-Ethyl acetate could be better separated from ethanol by doing which of the following?

A) Replacing helium with nitrogen as the carrier gas
B) Running the mixture through a longer column
C) Starting the chromatograph at a higher temperature
D) Increasing the carrier gas flow rate