                                    <option disabled selected value="option-0">Select an operation:</option>
                                    <option value="1">Direct (+,-)</option>
                                    <option value="2">Siblings (+), Direct (+,-)</option>
                                    <option value="3">Relatives (+,-), Direct (+,-)</option>
                                    <option value="4">Relatives (+), Direct (+,-)</option>
                                    <option value="5">Relatives (+, -), Direct (+,-)</option>
                                    <option value="6">Siblings (+), Relatives (+), Direct (+,-)</option>