To solve the problem it is simply necessary to apply the concepts related to the kinematic equations of motion and Newton's second law.
Newton states that Force is proportional to mass and acceleration, so
[tex]F = ma[/tex]
We know that in the absence of air resistance, in a sum of forces on the Glider there would be no horizontal component. In this way there would only be two forces, the lifting force and the force caused by the total weight of the Glider. By decreasing the weight the variation that would exist is clearly in its vertical stability. As regards speed or acceleration, they will remain the same. Recall that the acceleration is the change of speed, and in the absence of a force that modifies this in the horizontal component, then the balance will remain there and the speed will remain constant. There is no force that generates a change in its horizontal component and that can affect drag or thrust.
The correct answer is, E) The glider's speed will remain the same as it was