bestStock in the task:

bestStock({
    'CAC': 10.0,
    'ATX': 390.2,
    'WIG': 1.2
}) == 'ATX'
bestStock({
    'CAC': 91.1,
    'ATX': 1.01,
    'TASI': 120.9
}) == 'TASI'

sumTwo in the solve:

function sumTwo(a, b) {
    // sums two passed arguments

    // your code here
    return 0;
}