result of a function inner one other

if have a dir with:
Folder_a/subfolder_a/a.php
Folder_b/b.php

and one file a.php with one function that return some arguments
function A() {
$arr1 = array();
....
return $arr1;
}


how can inner file b.php to write a B function that recall function A
and return always the same arguments?


function B() {
recall here function A
}
.