code: public FluentSelect selectByIndex(final int index) {
          executeAndWrapReThrowIfNeeded(new SelectByIndex(index), Context.singular(context, "selectByIndex", null, index), true);
          return new FluentSelect(super.delegate, currentElement.getFound(), this.context, monitor, booleanInsteadOfNotFoundException);
      }
docs: Select the option at the given index. This is done by examing the "index" attribute of an
  element, and not merely by counting.
  
  @param index The option at this index will be selected