What is the output of the following code? class Number { private $v = 0; public function
__construct($v) { $this->v = $v; } public function mul() { return function ($x) { return $this->v
* $x; }; } } $one = new Number(1); $two = new Number(2); $double =
$two->mul()->bindTo($one); echo $double(5);
A.
5