Question:What is the output of the following script?<?php
class ClassOne {
protected $a = 10;
public function changeValue($b) {
$this->a = $b;
}
}
class ClassTwo extends ClassOne {
protected $b = 10;
public function changeValue($b) {
$this->b = 10;
parent::changeValue($this->a + $this->b);
}
public function displayValues() {
print "a: {$this->a}, b: {$this->b}\n";
}
}
$obj = new ClassTwo();
$obj->changeValue(20);
$obj->changeValue(10);
$obj->displayValues();
?>
A a: 30, b: 30
B a: 30, b: 20
C a: 30, b: 10
D a: 20, b: 20
E a: 10, b: 10