def single_option(list_like):
    """
    checks if a single option is true
    :param list_like: a list-like of bools
    :return: true if exactly 1 is true, else returns false
    """
    trues = 0
    num = 0
    for i, b in enumerate(list_like):
        if b:
            trues += 1
            num = i + 1
            if trues > 1:
                return 0
    return num