Final answer:
Gentamicin, an aminoglycoside, is most likely to cause nephrotoxicity because of its known potential for causing renal damage.
Step-by-step explanation:
Out of the drugs listed, Gentamicin would be the most likely to cause nephrotoxicity. Aminoglycosides like gentamicin are known to be potent broad-spectrum antibacterial agents that bind to the 30S subunit of bacterial ribosomes. However, these drugs have been shown to be nephrotoxic, which means they can be damaging to the kidneys. While drugs such as enrofloxacin, amoxicillin, and cephalexin have their own range of side effects, gentamicin's known potential for causing renal damage stands out among the options provided.