Coenzyme F₄₂₀ (a 5-deazaflavin) is a proton translocating electron transport coenzyme present in membranes of certain methanogens. The figure shows the oxidized and the reduced form of F₄₂₀: H atoms are omitted; R symbolizes the long C₁₇H₃₀N₂O₁₅P side chain.

Determine the oxidation state of the C atoms (indicated by drop down menues) and explain the differences between the oxidized and the reduced form of F420.