//Html code

<select-dropdown>
      <div class="below" style="width: 696.8px; top: 32px; left: 0px;">

          <!---->

          <div class="options">
              <ul>
                  <!----><li class="highlighted">
                      <!---->
                      <!----><span>TLrxCq</span>
                  </li>
                  <!---->
              </ul>
          </div>
      </div>
    </select-dropdown>

    //C# code

     var selectElement = new SelectElement(BrowserHelper.WebDriver.FindElement(By.XPath("//*[@id=\"Organization\"]/select-dropdown")));
            selectElement.SelectByText(org);