What is the conclusion of `alpha`-ray scattering experiment?

Explanation

The conclusion of `alpha` -ray scattering experiment is atoms inside gold are closely packed, `alpha` particles must have passed through the atoms.
(a) Since most of the `alpha` - particles simply passed through, most part of the atom should be empty space.
(b) Since a few of the`alpha` particles got deflected by small angles, they must have come across a positive part which would repel them.
(c) Since only one out of 20000 `alpha` particles retracted then path, the size of the positive part in the atom should be extremely small, only those particles which made a head on collision with the nucleus would retrace their path.