In IR Spectroscopy, the C-O Bond Has a ________ Frequency

In IR spectroscopy, the C-O bond has a ________ frequency than the C-N bond because ________.

A) higher; an O atom has more mass than an N atom
B) lower; an O atom has more mass than an N atom
C) higher; an O atom has more electronegativity than an N atom
D) lower; an O atom has more electronegativity than an N atom
E) higher; an O atom has an even number of neutrons