class C{
    public $C = 'Cname';
}

class B extends  C{
    public $B = 'Bname';
}

class A{
    
    public $B;


    function load()
    {
        $this -> B  = new B();
    }
}

$A = new A();
$A -> load();

echo $A -> B -> C;
echo $A -> B -> B;