Select the best definition of Femoral nerve.

A. A major nerve that passes through the carpal tunnel and supplies thenar muscles and sensation to the lateral hand. B. The principal nerve of the anterior thigh, supplying quadriceps and enabling knee extension. C. An arterial anastomotic ring at the base of the brain connecting anterior and posterior circulations. D. A specialized pacemaker region located near the superior vena cava in the right atrium.