A

To determine the acceleration of a body on a rough inclined plane, we apply the forces acting on the body. The forces acting on the body include:
1. Gravitational force (mg) acting vertically downward.
2. Normal force (N) acting perpendicular to the inclined plane.
3. Frictional force (f) acting opposite to the direction of motion up the incline.
The net force along the incline can be expressed as:
Net force = mg sin(θ) - f
Where f = μN and N = mg cos(θ); thus, f = μmg cos(θ).
Substituting this into the net force equation, we get:
Net force = mg sin(θ) - μmg cos(θ)
Therefore, the acceleration a is given by Newton's second law:
a = \frac{Net force}{m} = g sin(θ) - μg cos(θ)
Therefore, the correct expression for the acceleration of the body on a rough inclined plane is derived as per option A.