The performance of various XC functional approximations has been tested for K-shell excitation energies (1s → virtual) involving 1s orbitals of the elements C, N, O, and F. These methods include both the "full corehole" approach, otherwise known as the ∆SCF method or excited-state Kohn-Sham theory, but also fractionalelectron approaches that originate in Slater's transition state idea and several variants thereof. The overall conclusions are as follows.