I,m disappearing for a week, so this is an interim thought. If you have an aircraft with a low thrust line that passes through the CG and a high drag line, then in steady flight there is a nose up couple from thrust/drag. In steady flight this is exactly balanced by a nose down couple, which might be lift/weight, the tail or both or either. If you then increase thrust there will be no additional coulple about the CG, but surely there will be a larger thrust/drag couple now affecting the aircraft, and if this is not balanced the nose will rise.
The reason I brought this up is that the JAR question offered both thrust line lower than the CG and lower than the drag line as options, and we suspect the question is invalid. If it is invalid, someone may have failed his exam on a duff question, and we need to straighten out the question bank.
Of course, natural longitudinal stability will bring the nose up as speed increases, but that doesn't figure in this question.
Much appreciate your help, back in seven days.
Dick