<prompt> Confirmatory tests for Corynebacterium diphtheriae isSerological testsIsolation in selective mediaTest for toxinNone of the above  <response>: Selective media for Corynebacterium diphtheriae is Tellurite blood agar. Several modifications of Tellurite blood agar have been utilized, such as McLeods and Hoyles medium. Tellurite inhibits the growth of most of the other bacteria acting as a selective agent for diphtheria bacilli. Diphtheria bacilli reduce Tellurite to metallic tellurium which is incorporated in the colonies giving them a grey or black colour. Reference: Textbook of Microbiology; Anathanarayan and panickers; 10th edition; Page no: 242 