The empirical formula is a chemical formula that provides the smallest, whole number ratio of elements in a compound. What is the empirical formula for a substance that contains 40.00% carbon, 6.714% hydrogen, and 53.29% oxygen by mass?

a) C₃H₄O₂
b) C₄H₆O₄
c) C₂H₄O₂
d) C₃H₆O₃