Which of the following observations point to the equivalence of inertial and gravitational mass
(a) Two spheres of difference masses dropped from the top of a long evacuated reach the bottom of the tube at the same time.
(b) The time-period of a simple pendulum is independent on its mass.
(c) The gravitational force on a particle inside a hollow under isolated is zero.
(d)For a mass in a closed cabin that is falling freely under gravity, gravity 'disappears'.
(e) An astronomer inside a spaceship orbiting around the Earth fells weightless.
(f) Planets orbiting around the sun obey kepler's third law (approximately).
(g) The gravitational force on a body due to the Earth is equal and opposite to the gravitational force on the Earth due to the body.

Explanation

All axcept (c ) and (g).