如何在AngularJs中设置单选按钮初始选中？

<div ng-app="myApp" ng-controller="myCtrl">
  <label>
    <input type="radio" ng-model="selectedOption" ng-value="'option1'" ng-checked="selectedOption === 'option1'">
    Option 1
  </label>
  <label>
    <input type="radio" ng-model="selectedOption" ng-value="'option2'" ng-checked="selectedOption === 'option2'">
    Option 2
  </label>
</div>

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.7.9/angular.min.js"></script>
<script>
  var app = angular.module('myApp', []);
  app.controller('myCtrl', function($scope) {
    $scope.selectedOption = 'option1'; // 设置初始选中状态为Option 1
  });
</script>