Three density functionals from different rungs on the Jacob's ladder of DFT were selected for the benchmark. They are the second-rung BLYP GGA functional, which have been used in AIMD studies of the same complex before, the fourth-rung B3LYP hybrid functional, and the fifth-rung B2PLYP double-hybrid functional. While far from an exhaustive benchmark of the density functional-jungle, this selection systematically increases the detail with which first exchange and then correlation terms are included in the functional describing the electronic density.