$v$ from the left of point **A**. Then it passes points **A** and **B**, finally arriving at point **C**. It stops for a moment there at point **C**, and then starts to move back to point **A**. Which of the following statements is correct?

a) The charged particle is negatively charged.

b) The magnitude of the kinetic energy when the charged particle passes point **B** is half the kinetic energy when the charged particle passes point **A**.

c) The force acting on the charged particle at point **C** is not zero.