Answer:
The correct option is;
The acceleration remains constant
Explanation:
The acceleration is due to the force of gravitational attraction between the text book and the Earth
According to Newton's law of gravitation, there is an attractive force between all objects given by the following relation;
F = G×M₁×m₂/r²
Where;
G, M₁, m₂, and r are constant such that we have;
G×M₁/r² = Constant = The acceleraton due to gravity, g
F = g×m₂
So the acceleration of the textbook as it is being attracted by the force of gravity towards the ground (Earth) is remains constant.