Official solution
p \[ \to \] (q \[ \vee \] r)
= \[ \sim \] p \[ \vee \] (q \[ \vee \] r)
\[ \sim \] p \[ \vee \] (q \[ \vee \] r) is false when
(1) \[ \sim \] p = False \[ \Rightarrow \] P = True
and (2) (q \[ \vee \] r) is false \[ \Rightarrow \] q and r both are false.