**Core Concept**
The question is testing the student's knowledge of cephalosporin antibiotics, specifically the differences between generations and their routes of administration. Second-generation cephalosporins are a class of beta-lactam antibiotics that are effective against Gram-positive and some Gram-negative bacteria.

**Why the Correct Answer is Right**
Cefalexin is a second-generation cephalosporin that can be administered orally. It is effective against a wide range of bacteria, including Staphylococcus aureus and Streptococcus pyogenes. Cefalexin works by inhibiting cell wall synthesis in bacteria, ultimately leading to bacterial cell death.

**Why Each Wrong Option is Incorrect**
**Option A:** Cefaclor is a second-generation cephalosporin, but it is typically administered orally in the form of a suspension, not as a solid tablet.
**Option B:** Cefuroxime is a second-generation cephalosporin, but it is primarily administered intravenously or intramuscularly, not orally.
**Option C:** Cefadroxil is a first-generation cephalosporin, not a second-generation cephalosporin, and it can be administered orally.

**Clinical Pearl / High-Yield Fact**
Second-generation cephalosporins like cefalexin are often used to treat skin and soft tissue infections, as well as respiratory tract infections.

**Correct Answer:** C. Cefalexin