Array combinatorics in javascript, It’s wrong?

I have created this script due to the need to perform unique combinations when I receive n number of arrays, it works, however when I want to store in a final array it writes something different. Thank you very much for your help and I hope that the script will be useful to those who need it.

let options = {
            "A": ["A1", "A2", "A3", "A4"],
            "B": ["B1", "B2"],
            "C": ["C1", "C2", "C3", "C4", "C5"],
        };

        let keys = Object.getOwnPropertyNames(options);
        let size = keys.length;

        let final = [];

        function combinate(n, o) {

            for (let i = 0; i < options[keys[n]].length; i++) {

                if (n === (size - 1)) {
                    o = {};
                }

                o[keys[n]] = options[keys[n]][i];

                if ((n - 1) >= 0) {
                    combinate(n - 1, o);
                }

                if (n === 0) {
                    console.log(o);
                    final.push(o);
                }

            }

        }

        if (size > 0) combinate(size - 1, {});

        console.log("-----------------------------------")
        console.log(final);