取消选中单选按钮Angular 7 Bootstrap 4

<div class="form-check">
  <input class="form-check-input" type="radio" name="exampleRadios" id="radio1" value="option1" [(ngModel)]="selectedOption">
  <label class="form-check-label" for="radio1">
    Option 1
  </label>
</div>
<div class="form-check">
  <input class="form-check-input" type="radio" name="exampleRadios" id="radio2" value="option2" [(ngModel)]="selectedOption">
  <label class="form-check-label" for="radio2">
    Option 2
  </label>
</div>
<button (click)="cancelSelection()">取消选中</button>

import { Component } from '@angular/core';

@Component({
  selector: 'app-example',
  templateUrl: './example.component.html',
  styleUrls: ['./example.component.css']
})
export class ExampleComponent {
  selectedOption: string;

  cancelSelection() {
    this.selectedOption = null;
  }
}