Answer:
D.) NaOH
Step-by-step explanation:
Sodium always forms the cation, Na⁺.
Hydroxide is always written as OH⁻.
The compound should have an overall charge of 0 (be neutral). As you can see, the charges perfectly balance out (+1 + (-1) = 0). Therefore, there only needs to be one atom of each ion. The ionic compound is thus NaOH.