单项选择题
In a organic molecule, if the electron density between the carbon and oxygen of the carbonyl group, C=O, decreases (that is, the force constant of C=O decreases) affected by the adjacent functional group, the position of the stretching vibration peak of C=O should be()
A．Moving in the direction of high wave numbers
B．Moving in the direction of low wave number
C．No movement
D．The position keep unchanged, but the intensity of absorption peak changes
