The disease caused by a bacterium is
Diphtheria is an infection caused by the bacterium Corynebacterium diphtheriae. Symptoms include a sore throat, fever, barking cough, a grey or white patches develop in the throat. Diphtheria is usually spread between people by direct contact or through the air. It may also be spread by contaminated objects. So, the correct answer is 'Diphtheria'.