**Core Concept**
The extended activity of II-lactamases is a mechanism of bacterial resistance to beta-lactam antibiotics, such as penicillins and cephalosporins. These enzymes inactivate beta-lactam antibiotics by hydrolyzing the beta-lactam ring, thereby preventing the antibiotic from binding to its target, penicillin-binding proteins (PBPs).

**Why the Correct Answer is Right**
Extended-spectrum beta-lactamases (ESBLs) and AmpC beta-lactamases are examples of II-lactamases that exhibit broad-spectrum activity against a wide range of beta-lactam antibiotics. These enzymes can hydrolyze the beta-lactam ring of antibiotics, rendering them ineffective against bacterial infections. ESBLs and AmpC beta-lactamases are often produced by Gram-negative bacteria, such as *Escherichia coli* and *Klebsiella pneumoniae*, which can lead to serious infections and treatment challenges.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the inactivation of beta-lactam antibiotics by II-lactamases.
**Option B:** This option is incorrect because II-lactamases do not inactivate aminoglycosides, which are a different class of antibiotics that target the bacterial ribosome.
**Option C:** This option is incorrect because II-lactamases do not inactivate fluoroquinolones, which are a different class of antibiotics that target DNA gyrase and topoisomerase IV.

**Clinical Pearl / High-Yield Fact**
When suspecting an ESBL or AmpC beta-lactamase-producing infection, it is essential to use laboratory tests to confirm the presence of these enzymes and to select an appropriate antibiotic therapy, such as carbapenems or monobactams.

**Correct Answer: B. Carbapenems.**