The kinetic energy is calculated as:
\[ KE = \frac{p^2}{2m} \]
Given that all particles possess identical momentum, their kinetic energy is inversely related to their mass:
\[ KE \propto \frac{1}{m} \]
Consequently, the particle exhibiting the smallest mass will possess the highest kinetic energy.
Considering the provided particles:
\[ m_A = \frac{m}{2}, \quad m_B = m, \quad m_C = 2m, \quad m_D = 4m \]
Therefore, \(\frac{m}{2}\) (corresponding to particle A) exhibits the maximum kinetic energy.