Answer. Superior frontal gyrus.
Brief Discussion
The superior frontal gyrus is located just medial to the superior frontal sulcus. It forms the long limb of the 'L sign,' which can help identify the precentral gyrus (short limb of the sign) and central sulcus.
The superior frontal gyrus is contains motor association cortex posteriorly and heteromodal association cortex elsewhere. Importantly, the motor region contains the supplemental motor area. The heteromodal association cortex contributes to the prefrontal cortex, which has executive function.