The first four problems refer to the diagram below. Three charges are on a line with electrons (e, charge -e) at either end and an alpha-particle (a, charge +2e) in the middle. Both electrons are at the same distance D from the alpha-particle, and the magnitude of the force that one electron acts on another is F. e D a D e 1. (3 points) What is the magnitude of force between the alpha-particle and either of the electrons? (a) 0 (b) 3F (c) 7F (d) 8F