The PM7 method is to be used. This keyword is redundant because the default method in MOPAC2016 is PM7. See also Accuracy of PM7 and PM6-D3H4

Notes on PM7

PM7 uses a "D2" type correction for the elements:  H, He, B, C, N, O, F, Ne, P, S, Cl, Ar, Br, and Kr.  For the other elements, a core-core Gaussian attractive terms is used to mimic dispersion.  This means that some form of dispersion is present for all elements.  The core-core Gaussian terms are optimized to reproduce reference geometries and heats of formation.