In the weighted voting system$$ below, the weights represent voters$$ A$,$ B$,$C$,$ and D$,$ in that order.

$[13$, $5,3,4,8]$

a$)$ What is the quota?

b$)$ What is the weight of the voter A$?$ 

c$)$ What$$ are the winning$$ coalitions? Find critical voters in the winning coalitions.

d$)$ The Banzhaf power index of the voter C is $.$

d$)$ The Banzhaf power index of the voter D is