  An "ab initio" calculation of the Carbon-12 elastic form factor, and sum
rules of longitudinal and transverse response functions measured in inclusive
(e,e') scattering, is reported, based on realistic nuclear potentials and
electromagnetic currents. The longitudinal elastic form factor and sum rule are
found to be in satisfactory agreement with available experimental data. A
direct comparison between theory and experiment is difficult for the transverse
sum rule. However, it is shown that the calculated one has large contributions
from two-body currents, indicating that these mechanisms lead to a significant
enhancement of the quasi-elastic transverse response. This fact may have
implications for the anomaly observed in recent neutrino quasi-elastic
charge-changing scattering data off Carbon-12.
