<prompt> A child presents with fever and Lymphadenopathy. On examination a grey membrane can be seen over Left tonsil. Which of the following media is used for definitive diagnosis of organism?Lofflers serum slopePotassium tellurite agarChocolate agarTinsdale agar  <response>: For early diagnosis of C.diphtheria - Lofflers serum slopeFor defenitive diagnosis - Potassium tellurite agar. 