particle p is an electron and particle q is a neutron
i would say b
but i think i would need more information than that
quantum of energy is important because the energy of a particle, and also how long it has had that energy, with infinite precision. Quantum, in physics, discrete natural unit, or packet, of energy, charge, angular momentum, or other physical property. the term also applicable to quanta of other forms of electromagnetic energy such as X - rays and gamma rays.