Consider the following premises. For all x_14, x_14 is a sailor if and only if x_14 is an office clerk. James is an office clerk or James is not a sailor. Can we infer the following from them? James is a sailor if and only if James is an office clerk.
 From the fact that for all x_14, x_14 is a sailor if and only if x_14 is an office clerk we can infer that for all x_14, if x_14 were an office clerk, then x_14 is a sailor. From the fact that for all x_14, if x_14 were an office clerk, then x_14 is a sailor we can infer that if James were an office clerk, then James is a sailor. From the fact that James is an office clerk or James is not a sailor we can infer that if James were a sailor, then James is an office clerk. Finally, from the fact that if James were a sailor, then James is an office clerk, and that if James were an office clerk, then James is a sailor we can infer that James is a sailor if and only if James is an office clerk. Therefore, the answer is yes.