$parent Select Options

HTML

<div data-bind="foreach: someParent">
    <select data-bind="options: $parent.choices, 
                      value: $root.choice">
    </select>
</div>

JavaScript

function ViewModel() {
    this.someParent= ko.observableArray(["Whatevs"]);
    this.choices = ko.observableArray(["one", "two", "three"]);
    this.choice = ko.observable("two");
};

var vm = new ViewModel();
ko.applyBindings(vm);