Forms of if in C

The if statement can take any of the following forms:

if ( condition )

do this ;

if ( condition )
{
do this ;
and this ;
}

if ( condition )
do this ;
else
do this ;

if ( condition )
{
do this ;

and this ;

}
else
{
do this ;
and this ;
}

if ( condition )
do this ;
else
{
if ( condition )
do this ;
else
{
do this ;
and this ;
}
}

if ( condition )
{
if ( condition )
do this ;
else
{
do this ;
and this ;
}
}
else
do this ;