African sleeping sickness is caused by $..........$.

• A
  $Plasmodium$ $vivax$ transmitted by tsetse fly.
• B
  $Trypanosoma$ $lewisi$ transmitted by fleas.
• C
  $Trypanosoma$ $gambiense$ transmitted by $Glossina$ $palpalis$.
• D
  $Entamoeba$ $gingivalis$ spread by housefly.