A purple color develops as soon as all reactants are mixed together for the aldol condensation of benzil and dibenzyl ketone. This color is due to:
a. the production of a highly conjugated molecule.
b. decomposition of benzil.
c. the production of a reactive intermediate.
d. the presence of the carbanion of benzil.
e. decomposition of dibenzyl ketone.
Answer: a. the production of a highly conjugated molecule.