ANSWER : 42

Explanation : :You can designate certain arguments as optional by placing them at the end of the list and assigning them a default value of nothing.

ANSWER : get_memory_usage()

Explanation : :We can use the memory_get_usage() function, and to get the highest amount of memory used at any point, we can use the memory_get_peak_usage() function.

ANSWER : glob()

Explanation : :Here is an example- // get all php files AND txt files $files = glob(‘*.{php,txt}’, GLOB_BRACE); print_r($files); /* output looks like: Array ( [0] => phptest.php [1] => pi.php [2] => post_output.php . . . )

ANSWER : Magic Function

Explanation : :PHP functions that start with a double underscore – a “__” – are called magic functions in PHP. They are functions that are always defined inside classes, and are not stand-alone functions.

ANSWER : Only ii)

Explanation : :Except (a) others are invalid names. According to the specified regular expression ([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*), a function name like this one is valid.