In 1763, the Reverend Edmund Stone Suggested Chewing the Bark

In 1763, the Reverend Edmund Stone suggested chewing the bark of the English willow (Salix abla) to treat a fever because it grows in moist regions where one was likely to catch a fever, and "... many natural maladies carry their cures along with them, or their remedies lie not far from their causes." It took 50 years to isolate the active ingredient in the bark, which was named salicylic acid. By the end of the 19^th century, salicylic acid was used to treat rheumatic fever, gout and arthritis. Many patients complained of chronic stomach irritation, however. Because his father was one of these patients, Felix Hoffman searched for a less acidic derivative of salicylic acid. In 1898, Hoffman reported that the acetyl ester of salicylic acid was both more effective and easier to tolerate than the parent compound. He named the compound aspirin, taking the prefix a- from the name of the acetyl group and spirin from the German name of the parent compound spirsure. Aspirin is 60.00% C, 4.48% H, and 35.5% O by weight. What is the total number of C, H and O atoms in the empirical formula of this compound?

A) less than 15 atoms
B) between 15 and 20 atoms
C) between 20 and 25 atoms
D) between 25 and 35 atoms
E) more than 35 atoms