Which of the following variables does PHP use to authenticate a user?
i) $_SERVER[‘PHP_AUTH_USER’].
ii) $_SERVER[‘PHP_AUTH_USERS’].
iii) $_SERVER[‘PHP_AUTH_PU’].
iv) $_SERVER[‘PHP_AUTH_PW’].
a) i) and ii)
b) ii) and iv)
c) i) and iv)
d) ii) and iii)

Answer: c
Explanation: $_SERVER[‘PHP_AUTH_USER’] and $_SERVER[‘PHP_AUTH_PW’] store the username and password values, respectively.