A chromophore is: a. an unsaturated organic functional group that absorbs ultraviolet or visible radiation.
b. a biochemical species, such as NADH, that strongly absorbs ultraviolet or visible radiation.
c. an ion or complex of elements from the first two transition series that absorbs visible radiation.
d. a molecule that contains an electron-donor group bonded to an electron-acceptor. When radiation is absorbed, an electron is transferred from the donor to an orbital of the acceptor.