Let $Γ \equiv A : *, B : *, C : *$. Prove, by giving full derivations in $λD_0$:
(a) $\emptyset; \Gamma \; \vdash \; *:\Box$
(b) $\emptyset; \Gamma \; \vdash \; A : *$
(c) $\emptyset; \Gamma \; \vdash \; B : *$
(d) $\emptyset; \Gamma \; \vdash \; C : *$
The following derives all the results (a)-(d) in flag-format.
