Consider the following premises. If Richard were not excited, then David is curious. If David were curious, then Elisabeth is a politician. John is not drinking water. Richard is excited if and only if John is drinking water. Can we infer the following from them? Elisabeth is a politician or Richard is a musician.
 From the fact that Richard is excited if and only if John is drinking water, and that John is not drinking water we can infer that Richard is not excited. From the fact that if Richard were not excited, then David is curious, and that Richard is not excited we can infer that David is curious. From the fact that if David were curious, then Elisabeth is a politician, and that David is curious we can infer that Elisabeth is a politician. Finally, from the fact that Elisabeth is a politician we can infer that Elisabeth is a politician or Richard is a musician. Therefore, the answer is yes.