Which Characteristic of the Light Absorbing Regions of Chlorophylls and Carotenoids

Multiple Choice

Which characteristic of the light absorbing regions of chlorophylls and carotenoids most likely accounts for the ability of these molecules to absorb light?

A) ringed structures
B) the presence of aldehyde side-groups
C) the presence of magnesium
D) an extensive network of double bonds
E) long hydrocarbon chain