A young researcher set out to develop a method for quantifying the polycyclic aromatic hydrocarbon (PAH) content in a contaminated soil sample using open tubular gas chromatography. During the initial stages of method development, the researcher was unable to separate the early eluting compounds, anthracene and naphthalene, with baseline resolution. Select the possible modifications the researcher could make to improve the resolution. a. use a column with a larger inner diameter
b. increase the stationary phase thickness
c. increase the column length
d. increase the temperature
e. choose a different stationary phase