**Core Concept**
Aminoglycosides are a class of antibiotics that inhibit bacterial protein synthesis by binding to the 30S subunit of the bacterial ribosome. They are known for their broad-spectrum activity against both Gram-positive and Gram-negative bacteria, but their spectrum of activity can vary among different aminoglycoside antibiotics.

**Why the Correct Answer is Right**
The correct answer is Tobramycin because it has a wider spectrum of activity compared to other aminoglycosides. Tobramycin has excellent activity against Pseudomonas aeruginosa, Acinetobacter species, and Enterobacteriaceae, including many strains resistant to gentamicin and tobramycin is also effective against Streptococcus pneumoniae. Tobramycin's activity against these organisms makes it a valuable option in treating infections caused by resistant bacteria.

**Why Each Wrong Option is Incorrect**
**Option A:** Gentamicin is a broad-spectrum aminoglycoside but its spectrum is not as wide as Tobramycin's. Gentamicin lacks activity against Pseudomonas aeruginosa and some strains of Enterobacteriaceae.
**Option B:** Amikacin has a broad spectrum of activity but its spectrum is similar to Tobramycin's, and it is not considered wider.
**Option C:** Neomycin has a narrow spectrum of activity and is primarily used for topical use, making it less suitable as a systemic antibiotic.

**Clinical Pearl / High-Yield Fact**
Tobramycin is often used in combination with other antibiotics for the treatment of Pseudomonas aeruginosa infections due to its excellent activity against this organism.

**Correct Answer:** C. Tobramycin