Age 16 to 18 Short Challenge Level:
To do this question you need to be really sure what the two symbols
$\Rightarrow$ and $\Leftrightarrow$ mean.
$p\Rightarrow q$ essentially means that IF $p$ is True THEN $q$ is
$p\Leftrightarrow q$ means that $p$ is true if and only if $q$ is
true. Alternatively, they are either both true or both false.
To get started, pick one of the simpler looking statements for
Go through the other statements in turn and see which of them work
as $q$ in $p\Rightarrow q$. You will soon be able to pair-off
Finally, don't forget to read the details of the question