\item \lect Consider a formula $\varphi$ in propositional logic. In the
    following list, tick all statements that are true.

\begin{itemize}
\item[$\square$] If $\varphi$ is not satisfiable, $\neg \varphi$
    is valid.
\item[$\square$] If $\varphi$ is valid, $\neg \varphi$ is not
    valid.
\item[$\square$] If $\varphi$ is valid, $\neg \varphi$ is not
    satisfiable.
\item[$\square$] If $\varphi$ is not valid, $\neg \varphi$ is
    satisfiable.
\end{itemize}