Given the Lewis structure for SF4, determine the steric number of the central atom and the electron geometry.
a) Steric number = 5, Electron geometry = Trigonal bipyramidal
b) Steric number = 4, Electron geometry = Tetrahedral
c) Steric number = 4, Electron geometry = Trigonal planar
d) Steric number = 6, Electron geometry = Octahedral