You are trying to separate five proteins, which are listed below, by gel filtration chromatography. Which of the proteins will elute first from the column?

a) glutamine synthetase (621 kDa)
b) interferon-y (34 kDa)
c) hemoglobin (62 kDa)
d) cytochrome c (12 kDa)
e) RNA polymerase (99 kDa)