There Is Often Cross-Sensitivity and Cross-Resistance Between Penicillins and Cephalosporins

There is often cross-sensitivity and cross-resistance between penicillins and cephalosporins due to:

A) Similar renal excretion of both classes of drugs
B) When these drug classes are metabolized in the liver they both produce resistant enzymes
C) Both drug classes contain a beta-lactam ring that is vulnerable to beta-lactamase producing organisms
D) There is not an issue with cross-resistance between the penicillins and cephalosporins