Answer: A) C5H8O2
Explanation: Let's assume we have 100 grams of the unknown compound. We can then find grams for each element by multiply it's percentage times 100g. (e.g., carbon at 60% gives 60 grams of C). Then divide the mass of each element by it's molar mass. That will normalize the number of that element in relation to the others. E,g,, the 60 grams of carbon, divided by its molar mass of 12.01 g/mole gives 5 moles of C atoms. For H we get 8, and for O we get 2. That gives us the empirical formula C5H8O2