How did ernest rutherford know that an atom was mostly empty space

In 1909 Ernest Rutherford suggested an experiment using alpha particles and gold leaf . The results of this experiment led to changing the understanding of atomic structure . The "new" atom was mostly empty space and constituted the nucleus. Ernest Rutherford (1871-1937) was a New Zealandborn chemist who worked with J.J.Thomson at Cambridge University , was a pupil thereof . He conducted experiments with Thomson gas ions treated with X-rays in 1898. Rutherford alpha and beta rays proved the existence of the uranium atoms .

Aform of energy that is reflected or emitted from objects in the form of electrical and magnetic waves that can travel through space. there are many forms of  electromagnetic  energy including gamma rays, x rays, ultraviolet radiation, visible light, infrared radiation, microwaves and radio waves.

It is d, all the other ones say incorrect answer .