**Core Concept**
Trypsin is a serine protease enzyme that plays a crucial role in protein digestion in the small intestine. It specifically cleaves peptide bonds at the carboxyl side of basic amino acids, such as lysine and arginine.

**Why the Correct Answer is Right**
Trypsin works by forming a covalent bond with the oxygen atom of the serine residue in its active site, positioning the substrate for optimal hydrolysis. The enzyme's specificity for basic amino acids is due to the presence of positively charged amino acids in its active site, which facilitate the binding of negatively charged amino acid side chains. This allows trypsin to cleave peptide bonds at specific sites, releasing smaller peptides and amino acids.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because trypsin does not act on acidic amino acids, such as aspartic acid and glutamic acid.
* **Option B:** This option is incorrect because trypsin does not act on non-polar amino acids, such as alanine and valine.
* **Option C:** This option is incorrect because trypsin does not act on aromatic amino acids, such as phenylalanine and tyrosine.

**Clinical Pearl / High-Yield Fact**
Trypsin's specificity for basic amino acids is an example of substrate specificity, a fundamental concept in enzymology. Understanding the mechanisms of enzyme-substrate interactions is crucial for the development of drugs that target specific enzymes involved in various diseases.

**Correct Answer:** C. Arginine.