Which of the following is true regarding $HIV$,the agent responsible for $AIDS$?

• A
  $HIV$ is a non-enveloped retrovirus.
• B
  $HIV$ does not get eliminated but attacks the acquired immune system.
• C
  $HIV$ is an enveloped virus. It contains two identical molecules of single-stranded $RNA$ and two molecules of reverse transcriptase.
• D
  $HIV$ is an enveloped virus. It contains one molecule of single-stranded $RNA$ and one molecule of reverse transcriptase.