**Core Concept**
Fluoroquinolones are a class of broad-spectrum antibiotics that inhibit bacterial DNA gyrase and topoisomerase IV, crucial enzymes in DNA replication. Withdrawal of certain fluoroquinolones from the market is often due to concerns about adverse effects on tendons and joints, or other safety issues.

**Why the Correct Answer is Right**
Levofloxacin is a fluoroquinolone that has not been withdrawn from the market. It is a synthetic broad-spectrum antibiotic that acts by inhibiting DNA gyrase and topoisomerase IV, preventing bacterial DNA replication and transcription. Unlike some other fluoroquinolones, levofloxacin has been associated with a lower risk of tendon rupture and other adverse effects.

**Why Each Wrong Option is Incorrect**
**Option A:** Moxifloxacin was withdrawn in some countries due to concerns about its potential to prolong the QT interval, increasing the risk of cardiac arrhythmias.
**Option B:** Gatifloxacin was withdrawn from the US market due to reports of hypoglycemia and other adverse effects.
**Option C:** Lomefloxacin was withdrawn from the market due to concerns about its potential to cause phototoxicity and other adverse effects.

**Clinical Pearl / High-Yield Fact**
Be aware that some fluoroquinolones are more likely to cause adverse effects than others, and that certain patient populations (e.g. the elderly, those with a history of tendon disorders) may be at increased risk of these effects.

**Correct Answer: C. Lomefloxacin**