Which among the following is NOT dicarboxylic acid?

A dicarboxylic acid contains two carboxyl functional groups. Malonic acid (HOOC-CH$_{2}$-COOH), glutaric acid (HOOC-(CH$_{2}$)$_{3}$-COOH), and succinic acid (HOOC-(CH$_{2}$)$_{2}$-COOH) all possess this structural feature.

Caproic acid (CH$_{3}$(CH$_{2}$)$_{4}$COOH) contains only one carboxyl group, classifying it as a monocarboxylic acid.

The compound that is not a dicarboxylic acid is $\boxed{B}$.