Answer: Option (b) is the correct answer.
Step-by-step explanation:
Potential energy is the energy obtained by an object due to its position. Whereas kinetic energy is the energy obtained by an object due to its motion.
For example, when a charge moves from one point to another then it means the charge has come to motion.
Thus, we can conclude that potential energy of a stationary charge when it begins to move freely from one point to another under the influence of an electric field decreases.