The content (or rather lack of content) in this question suggests that it is from a JAR ATPL POF or Performance examination. Such questions often contain insufficient information to enable a single option to be selected. In this case the problem is made worse by the fact that no options have been given. I suspect that the question is intended to test the the effects of windshear and static longitudinal stability.
The sudden drop in headwind will cause a reduction in airspeed and dynamic pressure. But the inertia of the aircraft will (initially) hold ground speed constant. The reduced dynamic pressure will reduce the lift, thereby causing the aircraft to descend. The downward motion of the aircraft will give the relative airflow an upward component.
An aircraft that is longitudinaly stable will pitch into the relative airflow whenever the angle of attack is other than that for which it has been trimmed. Assuming that the aircraft was correctly trimmed prior to the wind change, its longitudinal stability wil cause it to pitch nose down, so that the original angle or attack tends to be restored.
When facing a question of this type in the JAR examinations the effect of stall and speed stability are best ignored unless there are specific clues to suggest that this is what the examiners are looking for.