def _strip_and_zip_options_and_bitmaps(cad):
  """Get dropdown info from cad, strip options and zip them with bitmaps.

  Args:
    cad: named tuple like (cad.id, cad.multi_choice_options,
                           cad.multi_choice_mandatory).

  Returns:
    [(dropdown_option, mandatory_bitmap), ...] for every option in dropdown cad
  """
  options = [opt.strip() for opt in cad.multi_choice_options.split(",")]
  if cad.multi_choice_mandatory is None:
    bitmaps = [None] * len(options)
  else:
    bitmaps = [bitmap.strip() for bitmap in
               cad.multi_choice_mandatory.split(",")]
  return zip(options, bitmaps)