Step 1: Recall the definition of tricarboxylic acids.
Tricarboxylic acids are organic acids that contain three \(\mathrm{-COOH}\) (carboxyl) functional groups in their molecular structure. Step 2: Analyze the given options.
Valeric acid and caproic acid are monocarboxylic acids.
Oxalic acid contains two carboxyl groups and is therefore a dicarboxylic acid.
Citric acid contains three carboxyl groups. Step 3: Conclusion.
Hence, citric acid is a tricarboxylic acid.