Which of the following are considered diphtheroids?

Diphtheroids are a group of bacteria that are primarily classified under the genus Corynebacterium and are similar in structure to Corynebacterium diphtheriae, the pathogen responsible for diphtheria. Among these, Corynebacterium xerosis is a recognized member of the diphtheroid group, known for its role as a commensal organism on human skin and mucous membranes.

Corynebacterium JK, although not a widely recognized or standard name in the literature, would suggest it belongs to the broader group of organisms similar to diphtheroids. The specific identification of this organism might vary, but it implies a relationship to the diphtheroid characteristics. As such, when considering the term “diphtheroids,” both Corynebacterium xerosis and the unspecified "Corynebacterium JK" can be concluded to fall under this classification.

Conversely, Corynebacterium diphtheriae is specifically distinguished as a pathogenic type and is primarily known for causing disease, rather than being categorized as a diphtheroid. This reinforces the distinction between pathogenic and non-pathogenic members within the Corynebacterium genus. Therefore, choices representing organisms that share the diphtheroid characteristics