Final answer:
Tetracycline (c) is not a ß-lactam antimicrobial because it does not contain the ß-lactam ring and works by inhibiting protein synthesis, unlike penicillin, cephalosporin, and carbapenem which all contain the ß-lactam ring and inhibit cell wall synthesis.
Step-by-step explanation:
The ß-lactam antimicrobials are a class of antibiotics that include penicillins, cephalosporins, carbapenems, and monobactams, all of which contain a ß-lactam ring essential for their antibacterial activity. These antibiotics work by inhibiting cell wall synthesis in bacteria. Among the options provided—penicillin (a), cephalosporin (b), and carbapenem (d) all fall within this category, as they possess the ß-lactam ring and inhibit the transpeptidase cross-linking activity of penicillin-binding proteins. On the other hand, tetracycline (c) does not contain the ß-lactam ring in its structure and acts by inhibiting protein synthesis, making it not a type of ß-lactam antimicrobial.