Two electrons, each with mass m and charge q, are released from positions very far from each other. With respect to a certain reference frame, electron A has initial nonzero speed v toward electron B in the positive x-direction, and electron B has initial speed 3v toward electron A in the negative x-direction. The electrons move directly toward each other along the x-axis (very hard to do with real electrons). As the electrons approach each other, they slow due to their electric repulsion. This repulsion eventually pushes them away from each other. Which of the following statements about the motion of the electrons in the given reference frame will be true at the instant the two electrons reach their minimum separation?

a. Electron A is moving faster than electron B.
b. Electron B is moving faster than electron A.
c. Both electrons are moving at the same (nonzero) speed in the opposite direction.
d. Both electrons are moving at the same (nonzero) speed in the same direction.
e. Both electrons are momentarily stationary.