The compound that is a carbohydrate among the options provided is C3H6O3 (which is also known as glyceraldehyde).
Carbohydrates typically have the general formula (CH2O)n, where n is the number of carbon atoms, and C3H6O3 fits within the range of simple carbohydrates.
The other compounds do not fit the definition of carbohydrates:
- C4H12N2 is likely an amine.
- HClO4 is perchloric acid, which is not a carbohydrate.
- Na2C2O4 is sodium oxalate, which is a salt and not a carbohydrate.
So, the correct answer is C3H6O3.