Consider the following premises. David is a musician or Charles is not drinking water. For all x_10, if x_10 were a musician, then x_10 is an office clerk. Can we infer the following from them? If Charles drinks water, then David is an office clerk.
 From the fact that for all x_10, if x_10 were a musician, then x_10 is an office clerk we can infer that if David were a musician, then David is an office clerk. From the fact that David is a musician or Charles is not drinking water we can infer that if Charles drinks water, then David is a musician. Finally, from the fact that if Charles drinks water, then David is a musician, and that if David were a musician, then David is an office clerk we can infer that if Charles drinks water, then David is an office clerk. Therefore, the answer is yes.