Select the proper IUPAC name for the following compound, including the (R) or (S) designation where appropriate. (2R, 3S)-2.3-difluorohexane (2S, 3R)-2, 3-difluorohexane (2R, 3R)-2, 3-difluorohexane (2S, 3S)-2, 3-difluorohexane