Array
(
    [0] => Array
        (
            [0] => abc
            [1] => ABC
        )

    [1] => Array
        (
            [0] => ab
            [1] => AB
        )

    [2] => Array
        (
            [0] => a
            [1] => A
        )

    [3] => Array
        (
            [0] => c
            [1] => C
        )

)