Array-Merge on an associative array in PHP

Question

How can i do an array_merge on an associative array, like so:

Array 1:

$options = array (
"1567" => "test",
"1853" => "test1",
);

Array 2:

$option = array (
"none" => "N/A"
);

So i need to array_merge these two but when i do i get this (in debug):

Array
(
    [none] => N/A
    [0] => test
    [1] => test1
)

Answer 1

$final_option = $option + $options;