Antibiotic that interferes with DNA function is:
(A) Metronidazole (B) Nystatin (C) Tetracycline (D) Sulphonamides
(A) Mechanism of Action

Metronidazole is a prodrug requiring reductive activation of the nitro group by susceptible organisms.
 Unlike their aerobic counterparts, anaerobic and microaerophilic pathogens contain electron transport components that have a sufficiently negative redox potential to donate electrons to metronidazole.
 The single-electron transfer forms a highly reactive nitro radical anion that kills susceptible organisms by radical-mediated mechanisms that target DNA.

Reference: Goodman & Gilman’s THE PHARMACOLOGICAL BASIS OF THERAPEUTICS THIRTEENTH EDITION
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