Boltzmann's Constant, K, Has a Value of 1

Boltzmann's constant, k, has a value of 1.381 × 10^-23 J/K. What is the significance of the constant?

A) It defines a characteristic energy at the microscopic level, given the temperature in kelvins.
B) It allows the pressure of the gas to be calculated, given the volume and temperature.
C) It measures the average kinetic energy of a molecule at a given temperature for each degree of freedom.
D) A) and B)
E) A) and C)