The question as originally asked by piper pervert asked what is the change in apparent wander rate. I believe that that was also the original wording in the Common Question Bank. In that case, the answer I gave (-2.6 degrees/hour) was correct and no correct answer option was given by the JAA. The nearest correct answer was -5 degrees/hour, but that was only the 'least worst' option of those given.
When we queried the question, I don't think we got a satisfactory reply. but I believe that the question has now been changed to "What is the average apparent wander rate", not "What is the change in apparent wander rate". In this case, the correct answer would be zero.