Which keyword must be added before $first variable on the third line of the above question to make $second and $first as distinct objects in PHP 5?

Which method introduced in PHP 5, is invoked just before an object is garbage collected?

Which one of the following method is invoked when an undefined method is called by client code?

Which one of the following method is invoked when a value is assigned to an undefined property?

PHP recognizes constructors by the name..