Crystalline orbitals obtained by the linear combination of atomic orbitals-self consistent field (LCAO-SCF) method at the Hartree-Fock (HF) and Kohn-Sham (KS) levels, are used to calculate the polarizability and related functions such as dielectric constant, reflectance, and energy loss function (ELF). Comparison of our calculations with experiment leads to a satisfactory agreement. The ELF spectra show clearly the energy ranges corresponding to the electronic excitations of the different orbitals. The carbon K-edge range is accurately analyzed in connection with the density of states.