Sort the following events into the order that they take place in phototransduction in response to a flash of light. Your answer would be a four-letter string composed of letters A to E, e.g. BCDEA.
(A) The cGMP level drops.
(B) The cGMP level rises.
(C) The Ca²? level drops.
(D) Retinal isomerizes to an all-trans configuration.
(E) Gt exchanges its bound nucleotide.