$4\mathrm{.}12(4\mathrm{.}16)$ e$.[$Note: part d is not assigned. Please provide your answer for part e$.]$ A quality control inspector examines four portable CD players and rates each as either 'acceptable' or 'unacceptable'. You record the number of units rated 'acceptable'.

$\{$A$,$A$,$A$,$A$\},\{$A$,$A$,$A$,$U$\},$ etc where A$=$Acceptable and U$=$Unacceptable.

$\{1,2,3,4\}$

$\{0,1,2,3,4,5\}$

$\{0,1,2,3,4\}$