Multiple choice php

What is the value displayed when the following is executed? Assume that the code was executed using the following URL:

testscript.php?c=25

  1. 25

  2. 10

  3. -5

  4. 0

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The URL parameter is ?c=25, so $_GET['c'] is 25. The global $e is 10. process(5) is called, so $c=5 (argument) and $d=25 (default). Calculation: 5 + 25 - 25 - 10 = -5. The return value is -5.