It would be zero. The weight of an object is the maximum at the surface of the earth. As you move the body closer to the center of the earth, the mass of the earth between the center of the earth and the body keeps decreasing. This causes the force acting from the center of the earth on the body to decrease. Furthermore, the mass of earth above the body(between the body and the surface of the earth) keeps increasing as you move it further towards the center. So the forces acting on the body by this mass would slowly become more than the force acting on?
