Which of the following is true about Corynebacterium diphtheriae?

Elek gel is a precipitation test. - Loeffler's serum slope is an Enriched medium. - Selective medium for C. diphtheriae is tellurite blood agar (eg. Mc Leod's and Hoyle's media or cystine - tellurite agar - Tinsdale medium). - Elek's gel is a precipitation test. It is an in vitro test for toxigenicity of the diphtheria bacillus. (Refer to the image below) - C. diphtheriae is gram positive, non-motile and non-capsulated, pleomorphic, non-sporing, slender rod- shaped bacilli. - All strains of C. diphtheriae show metachromatic granules on staining. Granules are composed of polymetaphosphate. Albe's stain is used to demonstrate Volutin/Metachromatic/Babes Ernst granules of Corynebacterium diphtheriae. It contains toluidine blue 'O' and malachite green. The bacilli are usually arranged in Chinese letter or cuneiform arrangement. Other stains : Neisser's stain, Ponder's stain.