Why Were Electric Eels Used to Discover NAChRs and Voltage-Activated

Why were electric eels used to discover nAChRs and voltage-activated sodium channels but not voltage-activated potassium channels?

A) nAChRs and voltage-activated sodium channels in eels are similar in structure and function to vertebrate channels so they make a good model to understand channels across phylogeny.
B) Electric eels provide an abundance of channels for biochemical purification prior to sequencing and cloning, but voltage-activated potassium channels were cloned using a different strategy.
C) A-type voltage-activated potassium channels are not expressed in electric eels, whereas those A-type channels are expressed in invertebrate Drosophila (fruit flies) .
D) Electric eels are aquatic organisms and thus sensitive to toxins like α-bungarotoxin, TTX, and STX, which assist in biochemical purification.
E) Shaker-type mutants were a fortuitous discovery that facilitated biochemical purification of voltage-activated potassium channels thus obviating the need an eel-like model system with abundant channels.