如何使按钮在内联单选按钮对齐？

<div class="form-group">
  <label>选择选项：</label>
  <div class="radio-inline">
    <input type="radio" name="option" value="1"> 选项1
  </div>
  <div class="radio-inline">
    <input type="radio" name="option" value="2"> 选项2
  </div>
  <button type="submit" class="btn">提交</button>
</div>

.form-group {
  display: flex;
  align-items: center;
}

.radio-inline {
  margin-right: 10px;
}

.btn {
  margin-left: 10px;
}