According to Bohr's planetary model of the atom, why don't the electrons collapse into the nucleus of the atom? The neutrons repel the electrons, keeping them in their energy levels.

The electrons are moving so fast that the pull from the nucleus is not enough to attract them.

The positively charged protons repel the negatively charged electrons, keeping them in their energy levels.

The electrons spin onto the nucleus, but they bounce back out into energy levels.