The correct answer is (d)
Work Step by Step
The naming of the compound is done in the following steps: 1. The compound is made up of non metals, has a hydrogen, and is designated as aqueous. So, it is an acid. 2. Since it is an acid and has oxygen, it is an oxyacid. 3. The oxyanion is nitrite ($NO_2^-$), so the name of the acid is $nitrous$ $acid$ Hence, the correct answer is (d).