Final answer:
The probability that an energy level 3 times higher than the Fermi energy is occupied by an electron is impossible.
Step-by-step explanation:
The probability that an energy level 3 times higher than the Fermi energy is occupied by an electron can be determined using the Fermi factor. The Fermi factor is the probability that a state of energy E is occupied. At T = 0 K, the Fermi factor can be calculated using the equation P(E) = Ce^(-E/kT). In this case, we can calculate the probability that the energy level is occupied by plugging in the values of T and E.
Since the question does not provide specific values of E and Ef, it is not possible to determine the exact probability. However, based on the information given, the probability can be either 0 or very low.
Thus, the correct answer would be option c) Impossible.