1 . Consider strings of length $89$, in which each character is one of the characters $a,b,c,d,e$. How many such strings have exactly $6$ letters $e$?
(a)
$\binom{89}{6}\cdot 5^{83}$
(b)
$5^{6}\cdot 4^{83}$
(c)
$\binom{89}{6}\cdot 4^{83}$
(d)
$\binom{89}{5}\cdot 4^{83}$
(e)
$\binom{89}{5}\cdot 5^{83}$