JSFiddle - React, Tailwind, and code Playground

HTML

<div data-bind="foreach:{ data: organizations, as: 'organization' } " class="accordion " id="accordionOrg">
    <table>
        <thead>
            <tr>
                <th>Billing Address</th>
                <th></th>
            </tr>
        </thead>
        <tbody>
            <tr>
                <td>
                    <select data-bind="options: organizationAddresses, optionsText: 'address',  optionsValue: 'organizationAddressId', value: organization.selectedBillingAddress, optionsCaption: 'Choose one'"></select>
                </td>
                <td>
                    <button data-bind="click: $root.addOrg(organization)" class="btn btn-small  btn-block">Add</button>
                </td>
            </tr>
        </tbody>
    </table>
</div>

JavaScript

var organizations = ko.observableArray();
var addresses = [{
    address: "Address Text 1",
    organizationAddressId: "Address Value 1"
}, {
    address: "Address Text 2",
    organizationAddressId: "Address Value 2"
}];


var vm = {
    organizations: ko.observableArray([{
        OrganizationId: 1,
        Name: "Org Name 1",
        SapId: "SapId1",
        UserId: "UserId1",
        Deleted: false,
        selectedBillingAddress: ko.observable(),
        organizationAddresses: addresses
    }]),
    activate: ko.observable(),
    selectedAddress: ko.observable()
};

vm.addOrg = function (organization) {

    console.log(organization.selectedBillingAddress())
}

ko.applyBindings(vm);