$HI$ cannot be prepared by the reaction of concentrated $H_2SO_4$ with $KI$ because:

• A
  $HI$ is a stronger acid than $H_2SO_4$.
• B
  $HI$ is more volatile than $H_2SO_4$.
• C
  $H_2SO_4$ is an oxidizing agent.
• D
  $H_2SO_4$ forms a complex.