The correct option is A Poisons released by living bacterial cells into the host tissue
Diphtheria is a serious bacterial infection usually affecting the mucous membranes of the nose and throat. The bacterium Corynebacterium diphtheriae causes diphtheria by releasing a poison that can cause grayish membrane to form and coat the inside of the victim's throat. The membrane can cause breathing problems.
So, the correct answer is 'Poisons released by living bacterial cells into the host tissue'.