A patient with peptic ulcer is treated with drug X. Several weeks later, the patient is given diazepam for treatment of anxiety, tension ,and insomnia. The patient falls asleep much more quickly and sleeps for a longer period of time than normally experienced with diazepam. Drug X is most likely to be which of the following?
A) Atropine B) Cimetidine C) Omeprazole D) Propantheline E) Ranitidine