Which of the following is a common laboratory acid?

Nitric acid is a common laboratory acid known for its strong acidic properties and its use in various chemical reactions and applications, such as in the production of fertilizers, explosives, and dyes. It is a highly corrosive and reactive compound, typically used in its concentrated form in laboratories.

The other substances listed do not qualify as common laboratory acids. Sodium hydroxide and potassium hydroxide are both strong bases and are used in laboratories primarily for their alkaline properties. Calcium carbonate is a neutral compound and is often used as a buffer in reactions rather than as an acid. Thus, nitric acid stands out as the correct answer due to its nature and prevalent use as an acid in laboratory settings.