$(4$pts$)$ Please classify each of the following as a violation of $($A$)$ confidentiality,

$($B$)$ integrity, $($C$)$ authentication, or $($D$)$ non$-$repudiation :

$($a$)$ A reads B$\text{'}$s email that is sent to $C$

A

$($b$)$ A sends an email on behalf of $B$ to $C$

C

$($c$)$ A denies sending an email to $C($although it was sent$)$

$D$

$($d$)$ A modifies the email sent from B to C

B