Explanation: Answer option A is correct.
The natsort() function is a sorting function. It uses a natural ordering algorithm to sort the contents of an array instead of using a simple binary comparison between the contents of each element. This function is mostly used to sort alphanumeric string. For example, if we have an array ("book12.pdf", "book11.pdf", "book2.pdf", "book1.pdf"), the standard sorting algorithm will give the following output:
Array
(
[0] => book1.pdf
[1] => book11.pdf
[2] => book12.pdf
[3] => book2.pdf
)
However, natural order sorting using the natsort() function will give the following output:
Array
(
[0] => book1.pdf
[3] => book2.pdf
[1] => book11.pdf
[2] => book12.pdf
)
Answer option B is incorrect. The ksort() function accepts an associative array and sorts its keys either alphabetically if any strings are present, or numerically if all elements are numbers. However, it does not sort the elements of the associative array.
Answer option C is incorrect. The sort() function is used to sort a given array either alphabetically if any strings are present or numerically if all elements are numbers. However, a user cannot pass an associative array to the sort() function. The reason behind this is that the values of the array are sorted as expected but keys are replaced by numerical indices that follow the sort order.
Answer option D is incorrect. The asort() function accepts an associative array and sorts its values either alphabetically if any strings are present or numerically if all elements are numbers. However, the asort() function preserves the array keys. Consider the following example:
<?php
$array = array("a1"=>'x',"a2"=>'e',"a3"=>'z');
asort( $array );
foreach ( $array as $keys => $values )
{
print "$keys = $values<br />";
}
?>
Output:
a2 = e
a1 = x
a3 = z
In the output, the array keys are preserved and array elements are sorted in the same way as in the sort() function.
Reference: https://www.php.net/manual/en/function.natsort.php