When Carbohydrates Are Oxidized, the C-H Bonds of the Carbohydrate

When carbohydrates are oxidized, the C-H bonds of the carbohydrate become C=O bonds of carbon dioxide. Oxidation is defined as a loss of electrons, but carbon does not become positively charged in the process. Why then is this considered oxidation?

A) The shared electrons in C-O bonds spend less time close to the carbon nucleus than the shared electrons in C-H bonds.
B) Electrons in the C=O bonds are higher energy than the electrons in the C-H bonds.
C) C=O bonds in CO₂ are double bonds, and C-H bonds are single bonds.
D) The phosphate groups of ATP are ionized, and carbons donate those electrons.