<prompt> Opacity around colonies of Clostridium perfringens is due to -Theta toxinLecithinaseDesmolaseCytokinin  <response>: Opacity around colonies of Clostridium perfringens is due to lecithinase. Option 1 Theta-toxin- hemolysin cytolytic toxin. Option 2 Nagler reaction: Shown by C. perfringens as opalescence on serum or egg yolk media due to Lecithinase C activity of alpha toxin, it splits lecithin into phosphorylcholine and diglyceride in the presence of Ca2 and Mg2 ions.Refer to the image below It is a neutralisation reaction. Option 3, 4 - Desmolase: It is not produced by Clostridium perfringens. - Cytokinins CK are a class of plant growth substances phytohormones that promote cell division, or cytokinesis, in plant roots and shoots. 