The answer is A. CH2.
Empirical formula is just the compound in its smallest formula, so take a look at the ratios. For every 3 carbon there is 6 hydrogen atoms. You can simplify the ratio of 3:6 by dividing by 3 as that’s a common factor. 3/3 = 1 carbon. 6/3 = 2 Hydrogen, so CH2. - Hope that helps!
