QUESTION $15$

Complete this Derivation $($either respond directly, or send your sollution to

my email and notify me$)$

$1|A^{{?}^{?}}B$

$2|(C_{v}vB)vv(A^C),$ conclusion: $C$

For the toolbar, press ALT$+$F$10($PC$)$ or ALT$+$FN$+$F$10($Mac$).$