Which of the following quantities does not remain conserved during pair production?

Which of the following quantities does not remain conserved during pair production?

Explanation
 In pair production, a high-energy photon converts into a particle-antiparticle pair (e.g., electron + positron).

The following quantities are conserved:
  • Energy
  • Momentum
  • Charge

However, mass is not conserved in the classical sense.
Instead, mass is converted into energy (or vice versa), following Einstein’s equation: E=mc^2