The ratio of charge and mass would be greatest forA Proton B Electron C Neutron D Alpha

The ratio of charge to mass would be greatest for an electron.

Here's why:

1. The charge of a proton, electron, and alpha particle is the same in magnitude but different in sign. Protons and alpha particles have a positive charge, while electrons have a negative charge. Neutrons have no charge.

2. The mass of an electron is much smaller than that of a proton, neutron, or alpha particle.

3. Since the ratio in question is charge/mass, and the charge is the same for the proton, electron, and alpha particle, the particle with the smallest mass will have the greatest charge/mass ratio.

4. Therefore, the electron, having the smallest mass, will have the greatest charge/mass ratio.